Wash the cucumber and cut into thin slices. Put potato salad in a bowl and stir in the cucumber slices. Cut lamb salmon crosswise in half and season with salt and pepper. Grill meat from one side for about 10 minutes.
In the meantime, cut the feta roll in half lengthwise and slice it. Turn the meat, immediately cover with slices of feta, sprinkle with thyme and grill again for another 10 minutes. Put potato salad in a bowl and sprinkle with fresh pepper.