First cut the salmon slices into wider strips, then into larger pieces. Peel the spring onions and cut into thin rings. Halve and core the cherry tomatoes.
Mix in a marinade from pepper, mustard, lemon juice, vinegar and oil, stir in the dill.
Mix the marinade, fish and vegetables together and leave to stand in the refrigerator for at least 1 hour, covered. The salad can also be left to stand overnight.