Clean and wash spring onions, dab dry and cut into fine rings. Mix vegetable stock and vinegar. Season with salt, pepper and 1 pinch of sugar. Add spring onions and stir in. Wash the asparagus, cut off the woody ends.
Cut asparagus diagonally into bite-sized pieces. Cook in salted water for 7-8 minutes. Meanwhile wash salmon, dab dry and cut into cubes. Season with salt and sprinkle with lemon juice. Bring fish stock to the boil in a wide pot. Add the salmon cubes and cook for about 10 minutes. Drain the asparagus and mix immediately with the vinaigrette. Wash the dill and shake dry. Pluck the flags from the stalks, except for a few for garnishing, and chop finely.
Add the salmon cubes and cook for about 10 minutes. Drain the asparagus and mix immediately with the vinaigrette. Wash the dill and shake dry. Pluck the flags from the stalks, except for a few for garnishing, and chop finely. Add dill and sprouts to the asparagus and fold in carefully. Place the salmon on top and garnish with the remaining dill and lemon wedges.