Wash and dry zucchini thoroughly. Slice zucchini down the middle, lengthwise.
Brush olive oil evenly on top of cut side of each zucchini half
Lightly sprinkle kosher salt and freshly ground black pepper over each zucchini half. If desired, add a light sprinkle of garlic powder and onion powder.
Heat outdoor or indoor grill on medium heat. Once hot, cook zucchini 3-4 minutes on one side, without moving them around. Use thin metal spatula to flip each zucchini half and cook 3-4 minutes on other side, just until zucchini halves have nice grill marks on them.
Serve warm. Garnish with lemon wedges, if desired.