Cook the quinoa according to package instructions.
While the quinoa is cooking, saute the red onion and zucchini in the olive oil. After about 7-8 minutes of cooking, add the corn. Stir and cook until heated through. Season with salt and pepper.
Once the quinoa is cooked, add the nutritional yeast, cumin, garlic powder, salt, and pepper. If the quinoa seems too dry, add a tablespoon or two of water and stir.
Spoon the quinoa into bowls. Top with the sauteed vegetables and sliced avocado. Season with more salt, pepper, and red pepper flakes if desired.