Position rack in centre of oven, then preheat broiler.
Combine quinoa with 2 cups water in a medium saucepan set over medium-high. Bring to a boil, then reduce heat to medium. Gently boil until quinoa has sprouted, about 10 minutes.
Gently boil until quinoa has sprouted, about 10 minutes.
Meanwhile, cut peppers in half lengthwise. Remove seeds and membranes. Rub inside and outside of peppers with oil, then place cut-side down in an 8x8-in baking dish. Broil, flipping halfway, until lightly charred and softened, about 8 to 10 minutes. Remove dish from oven. Preheat oven to 400F.
Drain quinoa well, then combine with beans, salsa, corn, spice blend and black pepper in a large bowl. Divide quinoa mixture among cavities of peppers.
Bake until peppers are fork tender, about 10 to 15 minutes. Serve peppers topped with avocado and cilantro. Serve with more salsa, if desired. Serve immediately and enjoy!