I smoke salmon regularly, using a deep roasting tin that I line with tinfoil. I sprinkle 4 teaspoons of tea leaves onto the foil and 1 teaspoon of sugar. Then I put a cake rack that I solely use for this onto the foil.
The rack is elevated a bit. I mix brown sugar with a tablespoon of rum and spread that over the salmon and leave it for 20 minutes. I then place the salmon onto the rack, sprinkle salt over it (sometimes also grated rind of a lime, some grated ginger and thinly sliced red chili) and then cover the tin tightly with foil to seal. I place the tin over my wok burner on my gas cooker and give it 5 or six minutes on a reasonably high flame depending on the thickness of the salmon.
I then turn the flame right down and give it another 12-15 minutes depending on the thickness of the fish. After that time I turn the gas off and leave the salmon, still covered, for at least 20 minutes or for much longer if I have the time.
The salmon is invariably lovely and moist.