Pics to come tomorrow. This is a recipe I got from someone at r/smoking years ago and has been my go-to ever since. I usually brush half the pieces with maple and half I leave alone. The ones without maple have a smokier taste and are a tad crustier, a taste and texture I prefer for smoked salmon. I often brine overnight, rack the fish on the counter and use a fan to form a pellicle while the smoker is heating up. Takes roughly six hours to cook at the low temp smoke setting on my pellet grill.
Recipes: Thaw fillets, remove skin, cut the fillets lengthwise right down the middle and cut these strips into 7" or 8" lengths (usually 1/3 of the length of the fillet).
Brine: Put 1/2 quart of apple juice in a pot on the stove, bringing to low boil & then down to simmer. Add to this; 6 ounces of soy sauce 1/2 cup of non-iodized salt 1/2 cup of brown sugar 1/2 tsp of Garlic powder 1/2 tsp of Onion powder 1/2 tsp of Cayenne pepper 1/2 tsp of Dried Bay Leaf Flakes (or 2 or 3 fresh bay leaves)
Stir until salt is dissolved. Then add 1 1/2 quarts of water & ice to cool quickly.
Leave the Salmon pieces submerged in this brine for 4 hours (under 1/2") to 6 hours (over 1/2")
Dry the salmon and put on rack in fridge overnight to form a pellicle.
Smoke on low until internal temp reaches 145+. Brush with maple syrup once an hour to keep moist.
Edit: and here's a progress pic. Peppered on the left, maple on the right. Finished product looked very similar but a bit darker. Taste and texture were great. Funnily, the maple finished first despite getting brushed hourly.
Also all natural