This originated with my brother Laurence, who accidentally over-marinated some salmon - and then over-smoked it! We discovered that we really liked it that way; enough so that I soon had a smoker (a Luhr-Jensen “Little Chief”) myself. You will need a smoker to make this. This amount of smoking also requires a good fatty fish, else you end up with a brick! Atlantic and King/Chinook are good; Sockeye is next best; avoid Coho/Silver, Chum/Keta, and Pink/Humback. The greater drying makes the smoked fish last longer.
Mix the marinade ingredients thoroughly. Skin the salmon and remove any obvious bones. Marinate it for 24 - 48 hours in the refrigerator, unsettling the pieces a few times during that period to ensure that the marinade reaches everything. Putting it all in 2 - 1 gallon Ziplock bags produces more consistent marination than using a bowl.
Pat the fillets dry with paper towels, spray-oil the smoking racks, and arrange the salmon on them. Put the thickest cuts on the bottom racks. Smoke for about 3 hours (I use 3 pans of hickory chips). Leave in the smoker for 24 hours total, to complete the drying.
Notes
Don't use previously-frozen fish; it's harder to skin.
Derived from a recipe in the Luhr-Jensen “Little Chief” booklet.