To cut down on "slime," soak okra in apple cider vinegar for 30 minutes. Soak skewers in water to keep from burning.

While okra and skewers are soaking, press garlic and kosher salt together in a small bowl to make a paste. add mayonnaise, olive oil, and lemon juice and mix well. Cover aioli and chill.

Rinse off okra and pat dry with a paper towel. Skewer okra and onion slices alternately.

Skewer tomatoes on their own skewers.

Spray all skewers with cooking spray and season with salt and pepper to taste.

Put all skewers on grill and cook over Medium heat 5 minutes, turning once. Remove tomatoes from grill.

Increase heat to High and cook okra and onions an additional 5-10 minutes or until okra is charred evenly.

Remove all vegetables from skewers and serve immediately with aioli.