Optional: salsa, sour cream and shredded Colby-Monterey Jack cheese
Prepare squash according to package directions. Meanwhile, in a small skillet, heat oil over medium-high heat. Add corn; cook and stir until lightly browned, about 5 minutes. In a small saucepan combine beans, water, chili powder, cumin and if desired, turmeric. Cook and stir over medium heat until mixture is heated through and liquid is almost evaporated, about 5 minutes.
Divide squash among 4 serving bowls. Top with bean mixture, corn, tomatoes, avocado, green onions and toppings of your choice.