Move an oven rack to the middle position and preheat oven to 400 degrees. Line a baking sheet with foil or parchment paper for easy cleanup.
In a small bowl, combine chickpeas with olive oil, basil, garlic powder, 1/4 teaspoon salt, and 1/8 teaspoon pepper. Spread in a single layer on the prepared baking sheet.
Bake for 30 minutes, stirring the chickpeas and rotating the baking sheet halfway through. Remove from the oven and cool slightly.
To make the quinoa:
Meanwhile, combine quinoa and water in a small microwave-safe bowl. Cover; microwave for 4 minutes on high. Remove from microwave, stir, and heat again for 2 minutes longer. Stir and let stand 1 minute in the microwave.
To assemble the salad:
Layer greens in the bottom of a bowl or on a platter. Arrange the grape tomato halves, cucumbers, bell pepper, olives, chickpeas, and quinoa in sections around the bowl. Spoon the hummus in the middle of the bowl and serve.