One skewer at a time, lay chicken on a lightly oiled barbecue grill over a solid bed of hot coals or high heat on a gas grill (you can hold your hand at grill level only 2 to 3 seconds) and rotate quickly to firm up the surface of the meat. When all skewers are on the grill, close lid of gas grill. Rotate skewers every 2 to 3 minutes until meat is lightly browned and firm, not squishy, at skewer (cut to test), about 10 minutes total.