As luck would have it, we have a batch curing in the fridge at this very moment! We love this stuff. There's a little Finnish deli in Thunder Bay, Ontario, and every year when we pass through with the MOOSE heading out on Lake Superior, we stop and stock up on 'suola kala' (salt fish) which is essentially gravlax.
We first acquire two equally sized fillets of salmon. For the cure mixture we use three parts white sugar, three parts pickling/canning salt, and one part white pepper. Some people also throw in some fresh dillweed, but we do not. We lay the first fillet, skin-side down, on Handy-Wrap with a little of the cure underneath. The bulk of the cure goes on the flesh side followed by the second fillet, skin-side up, with the last of the cure on top. The sandwhich is then tightly wrapped and placed in a glass pan in the fridge with a board on top and some weight, like a brick or some canned goods. The fish package is flipped over about ever 12 hours and in two days is done. Wash off the remaining cure, pat dry, and you have gravlax. Serve it by cutting thinly with a fillet knife at an angle just down to the skin. We like it on thin Finnish rye bread with raw onion, but some folks use lemon juice, capers, dill mustard, etc.
One caveat: do not attempt this with fresh water fish because of the likelihood of encountering parasites.
Bon appetit!
Al