Cook rice in salt water according to package instructions. Peel cucumbers, cut them lengthwise into halves, remove seeds and cut into pieces. Clean, wash and chop spring onions.
Heat 2 tablespoons of oil in a large wide pot. Sauté spring onions and cucumbers for about 3 minutes. Season with salt and pepper. Dust with flour and sauté briefly. Stir in 400 ml water and stock.
Bring to the boil and braise covered for about 10 minutes.
Meanwhile wash the dill and cut it finely. Wash salmon, dab dry and cut into large cubes. Heat 2 tablespoons of oil in a frying pan. Fry the salmon for about 3 minutes. Season with salt and pepper.
Stir the sour cream, horseradish and dill into the cucumber. Season to taste with salt and pepper. Arrange everything.