Cook the diced onion with olive oil in a small pot over medium heat until soft. Add the water, quinoa, chili powder, cumin, cayenne, and salt. Bring to a boil, then cover and reduce to a simmer for 15 minutes. Remove from heat, and leave the lid on to rest for 5 minutes.
Meanwhile, cut bacon into 1-inch pieces, and cook thoroughly in a separate pan. (I like cast iron for this.) Preheat your oven to 350.
Remove the stem, seeds, and white flesh from the bell peppers. Cut each pepper in half, forming six "boats."
Stir hot sauce and pinto beans into the cooked quinoa, along with about 2/3 of the cooked bacon. Reserve the extra 1/3 for topping. Place the bell pepper boats back in the cast iron skillet or in another baking dish, and stuff them with the quinoa filling.
Bake at 350 for about 25 minutes. I like the peppers to still be somewhat crisp and sturdy, but if you want them to be very soft, bake them for a little longer.
Serve topped with salsa, avocado, and the extra bacon bits.