Peel the kohlrabis and cut or slice it thinly. Blanch slices in boiling salted water for 1-2 minutes. Rinse immediately with cold water. Wash cucumber and spring onions. Cut both into diagonal slices or rings
Roast sesame seeds in a pan without fat until golden brown. Let it cool down on a flat plate. Mix vinegar in a bowl with sugar, sesame, salt and pepper. Fold in oil in a thin stream
Arrange cucumber and kohlrabi slices alternately on plates in a fan shape. Arrange radish sprouts in the middle of the plates. Drizzle with vinaigrette and garnish with spring onion rings