It's always best to smoke while fresh, but still good if frozen first. Always bleed your fish as soon as you catch it. Clean as soon as you're done fishing. Get on ice.
Here's a tip not too many seem to know. The skin side of the salmon seems to continue to exude slime, even after it's cleaned, if the skin is up against plastic. Wrap your fish in a dish towel, or couple of paper towels, before you put it into a gallon ziplock. I put two half-fillets, meat side to meat side, then wrap with towel. It doesn't even smell fishy when you open the baggie.
I use a big chief smoker. I like to use 2 pans of hickory chips, then finish with a pan of apple or alder chips over the course of about 4 hours. Hickory, cherry and mesquite give a sharp smoke flavor compared to apple and alder.
Invest a few bucks for a few glass one gallon jars for brining, if you have room to store them.
Basic brine is about a cup of salt, a cup of brown sugar in a gallon of water. Add to the brine things that you like. I like about 1/2 lemon (NOT that shit in a bottle) in a gallon of brine. I also like some hot sauce, just enough for some heat in the background. I like 2c of brown sugar myself. Dill is really good with most fish, try about 1-2 tblsp per gallon.
I've had raw onion taste great in the brine, but I've had it make the whole batch taste awful. If you want onion flavor, I think dried onion flakes are safer.
You can add a cup of soy sauce or teryaki. If you do, I would cut the salt back to about 3/4c.
Other spices depend on what you like. Garlic, curry powder, wine, rosemary....whatever.
Once you find the spices you like, WRITE IT DOWN, spice, quantity, amount of water, how long you soaked, how much you rinsed. It might be a while till you have another salmon, and if you're like me, you'll manage to forget something important. When you finally hit a HR with the spices, you want to be able to repeat it!
You'll hate yourself if you blow this. Experiment with different spices when you do small batches. Stick to your best-to-date recipe when you do large batches.
Cover fish completely with brine for 8-10 hours. The time is not too critical, but if it soaks a really long time, you need to rinse longer after you remove from the brine. When rinsing the fish after brining, test every 6-8 pieces to insure you're getting enough salt out of the flesh. Do this by touching your tongue to the meat side. If it tastes salty, it with be moreso after smoking. It can ruin your batch, and that sucks.
BE GENTLE WITH YOUR FISH when rinsing. Once you make it mushy, smoking doesn't make it firm again. Same with starting with a dark fish. If you wouldn't bake/fry/steam your fish, don't smoke it, release it. You want a fish that's shiny and when you push your thumb into the muscle, it's firm. If in doubt, let it go.
When I first started doing this, I smoked 16 chum salmon in three big chiefs. They looked fine and I caught them within a mile of salt water. That's a about 8-10 hours of filleting, de-boning (if it's just your family eating it, be a stud and take the pin bones out), butchering into chunks, making brine, rinsing, drying, loading onto racks, unloading, and discovering that it was mushy and strong flavored. That made for about 30 lbs of cat food. This was when I learned to test for firmness before I hit it 'em on the head.
Once you get the spices right for you, you can always make the best smoked fish on the planet....cause it's your favorite combination of flavors.
I place the fish skin down on a counter covered with bath towels, then lay towels over the top. GENTLY pat dry. Pepper liberally while it's all laid out, meat side up. Place fish on racks, put racks in stands.
Let stand for AT LEAST 2 HOURS. 4 is better unless it's hot weather.
Put the thick chunks on the bottom rack closest to the heat, thinnest on top shelf.
It takes a long time after chips are burned up. Thick fillets can take 12-16 hours in big chief. I understand that you can finish in the oven after chips burn and it's just as good, but I've never tried. Be interested if anyone else knows, from experience, if finishing in oven, or in the microwave is just a good, better, or worse than finishing in smoker.
After top no longer looks raw, start testing every hour or two for doneness by pressing with your finger. If you like your fish moist, it should feel like, um, pressing on a medium rare beef steak?. If you like it drier, it should feel like med. well done.
Let chunks cool. Place 2 paper towels on two paper plates. Put a single layer of fish on the towels on the plates. Put two paper towels on the layer of fish, and put two paper plates on the towels. Slide whole mess into a gallon zip lock. Put in fridge. The fish will re-hydrate a little in the fridge, and will actually give off quite a bit of water into the towels and plates. If they feel wet, change them. When the fish quits making the paper towels wet, package for long term storage.
Anyway, that was a lot longer than I thought it would be. There are lots of brines and methods on the net if you do some surfing. I used a dry rub once, and it was good. Google Salmon University would be a good place to start.
Fish ON!
Go Blazers