Pre-heat the oven to 350°F. Bring 2 cups of water to a boil in a medium saucepan. Add quinoa, reduce heat to medium-low, and cook covered for approximately 15 minutes. Remove from heat and set aside.

Fill a large pot with salted water and bring to a boil. Cut the tops off the peppers (about 1/2-inch from the stem side). Remove the seeds and membranes (feel free to dice the pepper tops and add them to the stuffing mixture later on). Add peppers to the pot and boil for 3 minutes. Promptly drain and rinse the peppers under cold water, and set aside to cool.

In a large skillet, heat 2 tablespoons of oil over medium-high heat. Add in the chopped onions and cook, stirring often, for 5 minutes until translucent. Add in the minced garlic and continue cooking for one minute more.

Reduce the heat to medium. Stir in the ground beef and cook until no longer pink. Add in the paprika, salt, and pepper. Stir in the corn, chopped tomatoes, jalapeño and black beans and cook for 5 minutes. Mix in the cooked quinoa and the cilantro, stir for a couple minutes more, and then remove from heat.

Fill each bell pepper with the quinoa-beef mixture and place in a 9x13-inch baking dish (add a couple tablespoons of water with a few drops of oil to the baking dish to help prevent the peppers from sticking).

Cover loosely with foil and bake at 350°F for 30 minutes. Remove the foil and top the stuffed peppers with some grated cheddar cheese in the last 5 minutes of cooking if desired.