Peel and clean the cucumbers, cut them in half lengthwise and remove the seeds. Dice cucumbers. Clean and wash spring onions and cut into thin slices. Heat the fat in a pot. Steam cucumbers and spring onions in the fat until transparent, except for a little bit for garnishing.
Pour in broth and wine, bring to the boil and simmer for about 5 minutes. Wash the dill, shake dry, pluck the dill pennants from the stalks and, except for something to garnish, cut finely. Cut salmon into strips.
Finely puree the soup with a hand blender. Stir in cream and season with dill. Season to taste with salt and pepper. Arrange soup in plates and sprinkle with salmon and capers. Garnish with dill and spring onions.