In a large mixing bowl, combine the ground beef or lamb, grated onion, minced garlic, parsley, mint, cumin, coriander, cinnamon, salt, black pepper, and cayenne pepper if using. Mix well until all ingredients are evenly incorporated.
Divide the mixture into 8 equal portions. With wet hands, shape each portion into a long, oval shape around a skewer, pressing firmly to ensure the meat adheres to the skewer.
Preheat your grill or grill pan over medium-high heat. Brush the kebabs lightly with olive oil to prevent sticking.
Grill the kebabs for about 10-12 minutes, turning occasionally, until they are browned and cooked through. The internal temperature should reach 160°F.
Remove the kebabs from the grill and let them rest for a few minutes before serving.
Serve the kafta kebabs.