In a large bowl, combine ground lamb, cumin, coriander, paprika, salt, pepper, grated onion, and minced garlic. Mix gently until just combined to avoid overworking the meat.
Cover the mixture and refrigerate for at least 30 minutes. This helps the flavors meld and the fats solidify, making the koftas easier to shape.
Cooking
Preheat your grill to medium-high heat. If using wooden skewers, soak them in water for 30 minutes to prevent burning.
Divide the lamb mixture into 8 equal portions. Shape each portion around a skewer, forming a long, oval shape. Handle the meat gently to keep it tender.
Brush the koftas lightly with olive oil. Place them on the grill and cook for 4-5 minutes per side. Look for a crispy, browned exterior and juicy interior.
Listen for a sizzle as the koftas hit the grill; this indicates the grill is hot enough to sear the meat properly.
Remove the koftas from the grill and let them rest for a few minutes. This allows the juices to redistribute, enhancing tenderness.