Preheat oven to 450°F. Coat large rimmed baking sheet with cooking spray. Spread eggplant cubes in single layer on baking sheet, spray lightly with cooking spray, and sprinkle with 1/4 tsp. each salt and pepper. Drizzle with 11/2 Tbs. oil; toss to coat. Roast eggplant 20 minutes. Turn; stir, then roast 10 minutes more, or until tender and browned. Cool on baking sheet.Bring large pot of salted water to a boil. Add bulgur, and boil 4 minutes. Mix in quinoa, and boil 12 minutes, or until both grains are tender, but still have some texture. Drain. Transfer to large bowl, and cool, fluffing with fork. Mix chopped mint and cilantro into grains, then mix in cooled eggplant and tomatoes.Whisk together lemon juice, remaining 2 Tbs. oil, 1/2 tsp. salt, and 1/2 tsp. pepper in medium bowl. Add chickpeas and red onion; marinate 15 minutes, then fold chickpea mixture into grains. Garnish with mint sprigs.