For the salad dressing, mix yoghurt, lemon juice and cream. Season with salt, pepper and sugar. Wash the chives, dab dry, cut into fine rolls and stir into the salad dressing, except for 1 teaspoon.
Clean, wash and cut iceberg lettuce into strips. Wash the cucumber thoroughly and cut into thin slices. Clean, wash and quarter radishes. Cut cheese into sticks. Mix lettuce, cucumber, radishes and cheese.
Arrange on four plates, add some sauce and sprinkle with the remaining chives. Add the rest of the sauce extra.