Cook orzo in salted water according to package directions; drain and rinse under cold water, transfer to a large bowl and combine with tomatoes and 1 tablespoon of the oil and garlic.

Meanwhile, spray the onions, bell peppers, and zucchini with olive oil; season with salt and black pepper, to taste.

Grill vegetables on a grill basket over oiled grates, covered, for 10-12 minutes or until lightly charred and tender, turning halfway.

Set aside on a cutting board to cool slightly, then dice into 1/2-inch pieces.

Toss the vegetables with remaining olive oil and vinegar, then top with chopped basil.