Place the salmon in a bowl and cover well with the sea salt. Cover the bowl with cling film and refrigerate overnight.
The next day, rinse the salmon. It should feel a little bit hard and leathery. Place in a clean bowl.
For the marinade, whisk together the olive oil, lemon juice, rind, dill, sugar, sherry and pepper. Pour over the salmon and leave, covered, in the fridge overnight.
Carve the salmon finely and serve with crisp salad leaves, oatcakes and mayonnaise.