Cucumber wash, peel, halve lengthwise, remove seeds and dice. Peel and finely dice the onion. Wash salmon, dab dry and cut into 4 pieces. Season with salt and pepper and sprinkle with some lemon juice
Fry the salmon in 1 tablespoon of hot oil for 1-2 minutes on each side. Add 300 ml water, wine and stock. Bring to the boil, cover and let simmer at low heat for about 10 minutes
Wash the dill and cut it finely. Add lemon zest and half of the dill to the fish
Fry the diced onion and cucumber in 1 tablespoon of hot oil. Add 3 tablespoons of water and steam for about 3 minutes. Season with salt and pepper
Take the salmon out and keep it warm. Stir mustard and crème fraîche into the fish stock, bring to the boil. Stir the starch and some water until smooth, stir into the sauce and simmer for about 3 minutes. Stir in the rest of the dill. Season sauce with salt, pepper, sugar and remaining lemon juice. Serve everything. Serve with boiled potatoes
Drink: cool white wine