Have not smoked a salmon filet yet. Sinful here in the PNW, I know...but have done them in the oven for work. I had the pleasure of working with a chef who was a graduate of the Johnson & Wales Culinary School back East and he turned me on to his marinade for Teriyaki Salmon. I assume you could do this in a smoker at higher temps for a fast finish or go the low & slow route like Ross posted. Regardless, here's the recipe out of my file....I do know it's very tasty done in the oven. If you do try this version in your smoker I'd be interested in any input.
TERIYAKI SALMON FILETS
¼ cup Soy Sauce (Kikkoman preferred, or any ‘naturally brewed‘ soy)
¼ cup orange juice
1 tbl. chopped garlic
2 tbl. white wine
2 tbl. minced ginger
2 tbl. Toasted sesame oil
2 tbl. Brown sugar
2 tbl. Rice wine vinegar (unseasoned)
2 green onions (scallions), chopped
Place all ingredients in a small bowl and whisk to dissolve sugar.
Place salmon filets in a large zip-lock baggie and pour marinade in.
Marinate salmon 2 hours, turning baggie occasionally so fish marinates equally.
Place salmon filets on a lightly oiled baking sheet and pour marinade over. Cover using either tinfoil ‘tent’ or another baking pan, inverted, on top. You don’t want the tinfoil touching the fish. Place in a preheated 350 degree oven for approx. 14-15 minutes. Salmon should just ’flake’ when tested with a fork.
Serve with Jasmine or ‘sticky’ rice and your veggie of choice.
Garnish with additional chopped green onions, if desired.
This marinade is enough for about 4 filets or one ‘side’ of salmon. Double recipe for a large side of salmon or big filets. You want enough marinade so the fish is covered.