Mix yoghurt and mustard for the dressing. Season with salt, pepper, lemon juice and sugar. Wash the dill, dab dry and cut finely. Stir in half of the dill. Wash the cucumber and cut into very fine slices. Peel onion and chop very finely. Cut the sausage into cubes.
Wash salad, dab dry and pluck into bite-sized pieces. Mix salad, cucumber, pork sausage and onions. Arrange on four plates. Spread some dressing on top and sprinkle with the remaining dill. Add the rest of the dressing. Serve garnished with dill pennants as desired