Soak the buns. Peel and finely dice the onion. Squeeze out the buns. Knead minced meat, bread roll, onion cubes, egg, mustard and tomato paste. Season with about 1 tsp salt, about 1/2 tsp pepper and Italian herbs.
With moistened hands form small meatballs from it. Fry in hot oil at medium heat for 6-7 minutes on each side. Leave to cool down if necessary.
For the salad, wash and halve the cherry tomatoes. Cut 4 gherkins into slices, quarter the rest lengthwise. Wash chives, shake dry and cut into small rolls. Fold tomatoes, cucumber slices and chives into the potato salad.
Wash and drain the salad and parsley leaves. Arrange the meatballs on top. Garnish potato salad with the cucumber quarters.