When cooking grilled green onions it's important to position the green stems over a cooler part of the grill. Set up your grill for two zone grilling.
Heat part of the grill to medium heat, and leave the burners off next to the hot area. If you're using charcoal, pile the coals to one side of the grill.
24 green onions
1/4 cup vegetable oil
2 tablespoons cider vinegar
1/2 teaspoon minced garlic
1/2 teaspoon salt
1/2 teaspoon black pepper
Trim the roots and the tips of the green stems off of the onions. Combine the remaining ingredients, making a marinade. In a large glass baking dish, marinate the green onions for an hour.
Remove the green onions from the marinade and place on the grill. Position the white, root end over the hot part of the grill with the green tops over the cooler part. Grill for 4 minutes, turning once. Drizzle with some of the remaining marinade when the onions are served.