In a cast iron skillet (foil/grill pan) coat the bottom with olive oil. Use enough to coat the bottom of the skillet typically about 1-2 Tbsp.
Place the okra in the skillet then top with the garlic, onion, and corn meal.
Toss it together to mix then grill it on high heat, about 500*F.
It typically takes about 10-20 minutes, but keep a close eye as it will vary based on the heat of the grill. Continue turning it to be sure that it's evenly cooked.
We like ours to be slightly browned and toasty.
Notes
Remember to watch it closely as all grills will heat a bit differently.