Prepare the ingredients: Peel and slice the sausage into either fine slices or stripes, the cheese into fine stripes. Cut the gherkins into little cubes and half the onions before you cut them into thin slices. Add the ingredients to a large bowl.
Dress the salad with water from the gherkins preserve, vinegar and vegetable oil, then season to taste with sea salt and black pepper and toss gently.