Add the chopped pepper, onion, and olive oil to a small saute pan and cook over medium heat until the peppers are soft and the onions are translucent, about 6 minutes. Add the minced garlic the last minute of cooking and cook until fragrant.
In a large bowl combine the cooked vegetable mixture, 1 cup of the cheese, black beans, quinoa, corn, salsa, half of the cilantro, and spices. Stir well to combine.
Heat a heavy bottomed skillet on the stove-top over medium heat.
Place 1 tortilla on a plate or cutting board, spread a 1/4 cup of the black bean mixture and then 1/4 cup of shredded cheese evenly over the tortilla. Place a second tortilla on top. Carry the quesadilla on the plate or cutting board over to the hot pan and carefully slide it onto the hot pan.
Let the tortilla cook for a minute or so, until lightly browned, and then carefully flip it over and cook on the other side. The goal is to have warm filling and melted cheese without burning the tortillas, so keep an eye on things and lower the heat if the tortillas are cooking too fast, or if your stove tends to cook hot, start with a lower temperature.
Remove the warm quesadilla from the pan and transfer to a cutting board. Using a knife or pizza roller, cut the quesadilla into 6 or 8 wedges.
Serve right away additional salsa or some sour cream for dipping.