Preheat the oven to 375ºF. Spray a 9x13 baking dish with cooking spray. Set aside.
Place the quinoa in a fine mesh strainer and rinse throughly with cool water for at least two minutes. Drain. In a medium saucepan, heat 2 teaspoons olive oil over medium-high heat. Add the quinoa and cook, stirring, for about one minute. The quinoa should begin to dry out and pop a bit. Add the chicken stock. Stir and bring to a boil. Turn the heat down to low and cook, covered, for 15 minutes or until all the water is absorbed. Remove the pan from the heat and let stand, covered, for 5 minutes.
Meanwhile, in a large skillet, heat 1 tablespoon olive oil over medium heat. Add onions and peppers and cook, stirring occasionally until soft, about 7 minutes. Add garlic and zucchini and cook 5-10 more minutes, until the zucchini is soft and beginning to brown.
Fluff the quinoa with a fork and place it in a large bowl. Add onion mixture, beans, green chiles, tomatoes, corn, cumin, oregano, chili powder, lime juice, and salt to taste. Mix thoroughly and transfer to prepared baking dish. Bake 30 minutes, top with cheese, and bake 10 minutes more or until melted and just beginning to brown.
Adapted from Dough-Eyed GirlsLeftovers can easily be microwaved, but I like them best fried in a little olive oil over medium heat until brown and crispy.An Italian version of this recipe can be found here.