Place coriander seeds and cumin seeds in a small dry skillet, then set over medium heat. Cook, shaking the pan often, until the spices are fragrant. Transfer to a mortar, then finely grind with a pestle. Set aside.
Place loosely packed cilantro in the bowl of a food processor, then add red onion thinly sliced and garlic. Pulse until finely chopped
Place ground lamb in a large mixing bowl. Add the cilantro-red onion mixture, the ground spices, feta cheese, garam masala, Kosher salt, and black pepper. Use your hands to thoroughly mix. Cover with plastic wrap, then refrigerate.
Divide the mixture, then roll into round balls. Press a skewer into each portion of meat, then use your hands to press the mixture into a 3-inch oblong shape around the end of the skewer. Repeat until all kebabs are prepped.
Heat a grill over medium-high heat . Coat with grill spray, then carefully add the kebabs to the grill. Cook until they are browned on all sides and fully cooked.
Transfer to a large platter then serve with lime wedges, fresh mint, and thinly sliced red onion. I like to serve Greek yogurt garlic sauce on the side. Enjoy!