Cut the chicken fillet in half lengthwise, each. Pour red pepper flakes, salt, black pepper, oregano into a large bowl, add lime juice and oil, stir and roll the chicken fillet in this mixture on all sides.
Heat the grill to medium heat, place the fillets on it and cook for about 4 minutes on each side.
Grease pieces of Turkish flatbread with mayonnaise and put avocado, chicken fillet, and tomatoes on each piece. Decorate the sandwiches with parsley.