Preheat oven to 425 degrees.
Cut the squash in half, then scoop out the seeds.
Cover the bottom of a baking tray with a layer of water, then place each half of the squash facedown. Bake for 30-40 minutes (time will depend on the size of the squash). Squash should be soft enough to cut into with a fork.
While the squash is baking, cook the quinoa according to directions. When the quinoa is done, add in the beans, chopped peppers, cilantro, and chopped tomatoes. Mix together until everything is heated up. Set aside.
Using a fork, scrape the middle of each squash half to create a "bowl", leaving the squash in the center. Fill each half with the quinoa mixture.
Top each half with shredded cheese, then put back in the oven for about 5 minutes to melt the cheese.
Remove from oven and top with avocado slices, plain greek yogurt, and crushed red pepper.
Serve immediately and enjoy!