PREP: Spray a 6-quart slow cooker with nonstick cooking spray (or use a slow cooker liner). Add the uncooked quinoa to a fine mesh sieve and rinse under cold water for 1 minute. (This removes the natural bitter coating on quinoa).
VEGGIES: Finely dice the sweet peppers and poblano chili pepper (remove seeds from both). Add the chopped peppers, minced garlic, and diced onion to the slow cooker.
SLOW COOKER: Place the rinsed quinoa, drained and rinsed black beans, undrained diced tomatoes, and corn in the slow cooker. Add in the seasonings: chili powder, cumin, garlic powder, onion powder, paprika, and salt and pepper to taste (I add 3/4 teaspoon salt and 1/4 teaspoon pepper). Stir everything together and put on the lid.
COOK: Set to high and cook for 2-1/2 to 4 hours (See Note 1) or until the broth is completely absorbed and the quinoa is cooked through ("popped"). All slow cookers cook a little differently so make sure to occasionally check the dish to make sure the quinoa isn't burning or sticking all to the sides.
FINISHING: Once cooked through, fluff quinoa with a fork and then gently stir in the chopped cilantro, fresh lime juice, and any additional salt/pepper as needed. Sprinkle the freshly grated cheese on top and cover with the slow cooker lid to melt for 5-10 minutes. Once melted, gently stir the cheese through the dish (it will continue to melt more and make everything extra cheesy). Serve with any desired toppings (additional cilantro, diced avocados, diced cherry tomatoes, additional lime, etc.).
LEFTOVERS: We love adding this mixture into a large tortilla (with extra cheese), rolling it up tight, and placing it in a skillet to brown the edges (1-2 minutes, switching sides every 30 seconds at medium heat). So good!