Place a large tablespoon of coarse mustard in a large bowl. The mustard should definitely be grainy, because that`s that certain something. Mix the mustard with the oil. Add the vinegar (I prefer mild melfor) and the cucumber water. Mix everything well and season with salt and pepper.
Peel the onions, cut in half and then cut into fine, thin rings. Dice the pickles and apples. Add onion rings, cucumber and apple cubes to the salad sauce. Likewise add the sausage. Here in the south you can buy them already cut. If you cut the sausage yourself, it should by no means be too coarse - it is best to cut the sliced sausage and then cut strips around 3 mm wide.
Mix everything well and let it steep a little. If you want to have sausage salad in the evening, it is best to prepare it in the afternoon.
To serve, sprinkle some chives or fine spring onion rings on top.
A nice slice of farmhouse bread tastes best with it.