Move oven rack to the upper third area and then preheat oven to 400°F.

Spray large skillet with cooking spray and heat over high. Add naan bread and allow to cook for 1 minute on each side (a grill pan would work great here). Place the naan on a baking sheet. Cut onions into thirds and add to hot pan. Cook for 1 minute; turn over and cook an additional minute. Remove from pan and set aside.

Sprinkle a small amount of garlic powder onto each naan; drizzle with olive oil.

Thinly slice zucchini and place an even amount onto each naan, followed by corn and onions. Sprinkle with salt and pepper.

Slice avocado and tomatoes. Add tomatoes to naan and set avocado aside.

Bake for 8 minutes. Turn on broiler and broil for 2 minutes, browning the crust.

Remove from oven and top with avocado. Cut each into quarters; serve with chilled grapes.