Put the lentils in a sieve and rinse with cold water. Cook in boiling water for about 10 minutes. Drain the lentils and let them drain well. Peel onions and garlic and dice finely. Heat 1 tablespoon of oil and fry the onions and garlic for about 3 minutes until transparent. Stir in the contents of the bag. Mix with lentils, oat flakes and 2 tbsp yoghurt. Form the mixture into approx. 20 walnut-sized meatballs.
Clean, wash and spin dry the salad and cut into fine strips. Clean, wash and dry grate radishes and cut into fine slices. Cucumber wash, clean, grate dry and cut into fine slices. Mix the rest yoghurt, lemon juice and honey, season with salt and pepper. Mix salad, radish, cucumber and dressing. Put in a cool place.
Heat 3 tablespoons of oil in portions in a large frying pan. Fry the meatballs in portions, turning on each side for approx. 3 minutes. Arrange lentil meatballs and salad, sprinkle with cress.