Wash potatoes thoroughly and cook in boiling water for about 20 minutes. In the meantime wash tomatoes. Peel prawns, except for the tail fin, and remove the intestines. Wash shrimps, dab dry and season with salt and about 2 tbsp. lemon juice.
Clean, wash and chop the spring onions. Drain the potatoes, let them cool down briefly and cut in half. Alternately put shrimps, halved potatoes, spring onions and tomatoes on skewers.
Heat 4 tablespoons of oil in portions in a large, coated frying pan. Fry the skewers for 5-6 minutes, turning them in portions. Remove and keep warm. For the dip, wash the dill, pat dry and pluck the flags.
Cut the dill finely except for a few flags for garnishing. Mix quark, 1 tablespoon olive oil, 1 tablespoon lemon juice, dill and wasabi. Season to taste with salt, pepper and sugar. Arrange skewers on plates. Garnish with dill flags.
Add wasabi dip.