Step 1

For the Salmon Scrape the skin well and remove all bones (If any)Mix together the salt, sugar and pepper. Sprinkle half the mixture in the bottom of a roasting pan lined with plastic wrap (enough to tightly wrap the fish) Then sprinkle half the lemon zest and 1/2 the chopped dill.  Place fish skin side down in pan. Repeat the process on the flesh side of the fish.  Wrap up the fish,  place a brick or heavy cans on top of the fish.Place in refrigerator for 3 days.  Flip the fish over once each day. There will be a lot of liquid in the pan this is normal.After three days, scrape the seasoning off both sides of the fish.Cut the salmon into very thin slices and serve with the mustard sauce

Step 2

In a blender or processor, add salt to the egg yolk and blend.  Slowly pour in the oil while slowly blending until the sauce is a consistency like mayonnaise. Add in the sugar, vinegar, pepper and mustard and blend well.Remove and place in air tight container after stirring in the freshly chopped dill. The sauce will keep for about a week in the refrigerator. Serve alongside gravlax.