Cure the salmon:place the 4 fillets of salmon into a small bowl and mix with the salt, pepper, dill and lemon zest. Marinade for 30 mins, only. Wash under running water, and pat dry the fish. Refrigerate covered with cling film.
Make the cucumber salad:finely slice the cucumber. Place in a bowl, sprinkle with salt and leave and marinade for 30 mins. (The salt will remove the enzymes which can cause indigestion). Rinse under cold water, pat dry. Add vinegar, sunflower oil, dill and pepper. Taste to correct seasoning.
Make the horseradish cream: combine all the ingredients and season to taste, for more of a twang add some freshly grated horseradish.
To confit the salmon: preheat the olive oil to 55C: drop in the four pieces of salmon and cook for approximately 16-18 minutes at 45C. Probe temperature of oil. The aim here is not to cook the salmon but to change its texture and taste. Once you put the 4 fillets into the oil, the oil temperature will drop to approx 45C. It must be kept at this temperature so use a probe to check. The salmon will be uncooked yet creating a very pleasing taste and texture. If over cooked the salmon fillet will leak white proteins (albumen).
Serve by arranging the cucumber in the centre of the plates; place on the confit salmon pieces. Drizzle the horseradish sauce around. Arrange a few sprigs of dill and trout eggs on the sauce. When serving sprinkle a little fleurs de sel onto the salmon.