Peel, wash and halve the potatoes and cook in salted water for about 20 minutes. In the meantime, wash the fish, dab dry and cut into 4 slices. Sprinkle with salt and sprinkle with 2 tablespoons of lemon juice. Heat the wine and about 125 g water and steam the fish for 12-15 minutes at low heat. Mix sour cream and milk.
Season to taste with salt, pepper, sugar and 2 tablespoons of lemon juice. Wash the dill, dab dry and pluck flags from the stems. Coarsely chop the dill flags, except for a few for garnishing. Fold 2/3 of the dill into the sour cream. Wash and clean the cucumber, rub dry and cut into thin slices. Mix cucumber and cream sauce. Drain potatoes, toss in butter and sprinkle with remaining dill. Remove salmon from the stock. Arrange salmon, potatoes and cucumber salad.
Wash and clean the cucumber, rub dry and cut into thin slices. Mix cucumber and cream sauce. Drain potatoes, toss in butter and sprinkle with remaining dill. Remove salmon from the stock. Arrange salmon, potatoes and cucumber salad. Garnish with lemon and dill