Place the summer squash in a bowl and toss with 2 tablespoons of the olive oil and ¼ teaspoon of the salt until well coated.
Put the red onion in another bowl and toss with 1 tablespoon of the olive oil and ¼ teaspoon of the salt until well coated.
Add the tomatoes to a third bowl and toss with 1 tablespoon of the olive oil and ¼ teaspoon of the salt until well coated.
Grill the summer squash for about 4 minutes on each side, and grill the onions and tomatoes for about 2 minutes on each side.
Warm the pitas on the grill for about 3 minutes on each side. Remove the pitas from the heat and slather each with about ⅓ cup of the hummus.
Top each pita pizza with grilled summer squash, tomatoes and onions. If desired, season with additional salt and/or pepper, to taste. Cut each pita pizza into 8 slices.
Recipe by Go Dairy Free at https://www.godairyfree.org/recipes/grilled-vegetable-hummus-pita-pizza