In a bowl, combine the mayonnaise, minced garlic, and lemon juice. Set aside in the refrigerator.
Preheat the grill for high heat.
Spread some of the mayonnaise mixture on the cut sides of the bread, and sprinkle each one with feta cheese.
Brush vegetables with olive oil on each side. Add salt and pepper to taste, if you want. Place a large sheet of tin foil on the grill and brush with olive oil. (Or brush the grill itself.) Place bell peppers and zucchini closest to the middle of the grill, and set onion and squash pieces around them. Place the bread on the grill, cheese side up, on the upper rack if you have one. Cook for about 2-3 minutes and remove the bread; you just want to get the cheese melty. Check it often to make sure it doesn't burn.
Flip the veggies and cook for another 3 minutes. The peppers may take a bit longer. Remove from grill.
Layer the veggies on the bread. You can eat these open faced or top them with the other half of bread. (I feel like I just don't have enough carbs in my life, so I like to top it off.)
by The Food Charlatan
I highly recommend making your own focaccia bread. It makes it even more amazing. Plus your house will smell like pizza and everyone will love you.