Combine salt, sugar, zest, pepper, juniper, and dill in a bowl. Add gin; stir until mixture resembles wet sand.

Rinse salmon and pat dry. Line a baking sheet with plastic; scatter one-third of sugar mixture on it. Lay salmon, skin-side down, on sugar mixture; spread remaining mixture evenly over top. Wrap tightly in the plastic; place a second baking sheet on top and weigh down with canned goods. Refrigerate, flipping fish and pouring off excess liquid every 24 hours, for 3 days. Rinse excess sugar mixture off salmon; pat dry.

Place fish flesh-side down, and slide the tip of a long, sharp knife between flesh and skin at a short end. Using a paper towel to grip, gently pull skin off. Flip fish; thinly slice at a 45-degree angle. Serve with relish, roe, crackers, capers, creme fraiche, fennel, and onion.