Cut the cucumbers into slices. Clean, wash, halve and slice the radishes. Cut cheese and sausage into strips. Wash chives, dab dry and cut into small rolls.
Peel the onion and cut into fine strips. Whisk vinegar, vegetable stock, mustard, salt, pepper and 1 pinch of sugar. Fold in the oil. Mix cucumber, radishes, sausage, cheese and chives. Drizzle with the vinaigrette.
Marinate for about an hour. Arrange on plates and serve garnished with radish slices and chives.