Make a basting mixture of 1/2 cup vegetable oil, 1/4 cup vinegar, and a pinch of cumin.
Prepare the grill, and grill chicken for 5 minutes on each side.
Baste chicken several times during cooking.
Cut a piece of the chicken to check for doneness. If the chicken is still pink on the inside, place it back on the grill, checking frequently. Do not overcook.