Fry the gyros sliced in oil in a large pan. Bake the flatbreads in the oven at 200 degrees for about 5 minutes until they are crispy, quarter them. Cut each quarter so that a pocket is created. Cut the cucumber, tomatoes into thin slices, onion into thin rings. Fill the flatbread bags evenly with gyros, tzatziki quark, tomatoes, cucumber, onions, squeeze them lightly and serve in a napkin if desired.