In medium bowl combine lamb, onion, parsley, mint, cumin, marjoram, salt, and pepper; mix well.
Divide lamb mixture into 4 equal portions.
Form each portion into a sausage shape, pressing each onto a 12-inch wooden or metal skewer; transfer skewers to rack in broiling pan.
In measuring cup or small bowl combine oil, lemon juice, garlic, and paprika; using pastry brush, brush oil mixture over keftas, coating all sides.
Broil, turning once, until keftas are browned on all sides, 5 to 6 minutes on each side.