Wash the potatoes and cook in boiling water for 15-20 minutes. In the meantime, clean, peel and finely slice the cucumber. Wash and quarter the tomatoes. Drain potatoes, rinse with cold water, peel and slice.
Mix stock, vinegar and mustard. Add 4 tablespoons of oil and season with salt and pepper. Mix all salad ingredients and vinaigrette. Wash the chives, dab dry and cut into small rolls.
Add to salad and stir in. Let potato salad soak for at least 1 hour. Wash the meat, dab dry and season with salt and pepper. Whisk the egg and turn the meat one after the other in flour, egg and breadcrumbs.
Heat the remaining oil in a frying pan and fry the escalopes in it at medium heat for 3-4 minutes on each side. Arrange Wiener Schnitzel and potato salad on plates and serve garnished as desired with capers, 1 slice of lemon and chives.