Cut ham and tomatoes into 1×1 cm cubes . Cut the onion into 8 pieces and again in half or into 3 pieces each slice. Green asparagus (pre-boiled and cooled) – about 2 cm in length. Mix yogurt, mayonnaise and lemon juice. Stir and season the salad with the mixture. Add salt and pepper to taste. Refrigerate for 15 minutes.