Preheat indoor or outdoor grill to medium heat. You can also use a cast iron skillet like I did today. Worked great. Place turkey, onion, feta, cilantro, hot sauce, salt, pepper, garlic salt and red pepper flakes into a large mixing bowl. Gently combine all ingredients mixing gently until just combined. Form into 3-4 inch patties and place onto a plate or tray to get ready for grilling/cooking. When grill or skillet is hot, grill/cook each patty until internal temperature reaches 165 degrees flipping half way through. When done, transfer to a clean plate/tray and keep warm with foil over top while cooking the rest of the patties.