Rinse and drain the black beans thoroughly.
Heat the olive oil in a non-stick skillet over medium heat.
Add the diced red bell pepper and red onion, sautéing for 3-4 minutes until they begin to soften.
Stir in the black beans, ground cumin, garlic powder, sea salt, and black pepper, cooking for another 2 minutes.
Add the chopped baby spinach to the skillet and stir until just wilted, then remove the bean and veggie mixture from the heat.
Wipe the skillet clean and return to medium heat.
Place the whole wheat tortilla in the skillet and sprinkle half of the shredded cheese over one half of the tortilla.
Spread the bean and vegetable mixture over the cheese, then top with the remaining cheese.
Fold the tortilla in half and press down gently with a spatula.
Cook for 2-3 minutes per side until the tortilla is golden brown and the cheese is completely melted.
In a small bowl, mix the non-fat Greek yogurt with the fresh cilantro and a pinch of salt.
Slice the quesadilla into wedges and serve immediately with the cilantro-yogurt dip and salsa on the side.