I've never made or even tasted Rick's gravlax but I have made the Hairy Bikers version,they use sugar and golden syrup, so may taste less salty.
Here is the recipe:-
Mix together 2-3 tbs of couse salt, 3 tbs dill, 2 tbs caster sugar,1 tbs cumin,1 tbs golden syrup, pepper.
Sprinkle 1 tbs of couse salt on a double layer of foil, put one salmon fillet, skin down onto the salt. Spread the above mixture over the flesh and lay the second fillet flesh down on top. Sprinkle another tb of couse salt over skin then wrap up tightly and put into a deep dish and leave for 5 days, draining any liquid away after 2 days. When the 5 days is up, pour away any liquid, seperate the 2 halves and scrape away the herb and salt mixture and discard, dry the fillets well. slice thinly as possible.