Mix sugar, salt, and lemon peel in a small bowl.
Sprinkle the marinade over the salmon in a shallow dish.
Marinate for one hour and rinse under cold water.
Divide the salmon into four equal portions.
Heat olive oil in a pan to 45°C.
Add salmon to the oil, turn off heat, and leave for 20 minutes.
Cool the salmon and chill in the fridge.
Mix yoghurt, mustard, salt, sugar, lemon juice, and horseradish to make the sauce.
Cube the cucumber into 1cm pieces.
Combine cucumber with vinegar, salt, oil, and mustard to marinate.
Fry oiled rye bread until browned and break into rustic croutons.
Assemble the salmon with sauce, salad, croutons, and micro leaves.