For the sausage salad, first peel the sausage and cut it into slices as narrow as possible. Cut the onions into fine rings or slice them. Cut cucumbers into small cubes.
Peel and core the apple, cut into small cubes and mix on the spot with the lemon juice so that it does not discolor.
Stir through mustard, 7 tablespoons vinegar, cucumber water, sugar, salt and pepper. Stir in oil with a whisk. Cut chives into rolls.
Arrange sausage slices on a platter, overlapping slightly, and sprinkle with onions, diced cucumber and apple. Spread salad dressing evenly over sausage salad and sprinkle with chives.