The grilling goes quickly, so set up your workstation next to the grill before you begin: the plate holding the skewers, the bowl of sauce and a basting brush and/or the salt, and tongs for turning the skewers. If using the basting sauce, either dip each skewer in the sauce or brush the sauce on the skewers and then place directly over the heat. Grill the skewers, turning 3 or 4 times and basting with additional sauce, until the chicken is cooked through and the onions are scorched around the edges, about 5 minutes total.