Wash potatoes thoroughly and cook in boiling water for about 20 minutes. In the meantime, fry the diced ham in a pan until golden brown and let it cool down a bit. Peel onion and cut into fine rings, cucumber into thin slices. Stir sour cream, yoghurt, mayonnaise and gherkin water until smooth. Season with a little salt, pepper and 1 pinch of sugar. Take 1 tablespoon of diced ham and some onion rings aside for sprinkling.
Add the rest of the ham, onions and cucumber to the sauce. Wash the maties, dab dry and cut diagonally into pieces. Mix loosely with the sauce. Wash the chives, dab dry and cut into fine rolls. Arrange the matie in a bowl sprinkled with chives, remaining onion rings and diced ham. Serve with boiled potatoes