Heat the olive oil over medium heat in a large pot with a lid. Sauté the onions and peppers in the olive oil until the onions are soft and beginning to brown.
Add the spices and garlic and stir until they are fragrant and just beginning to brown and stick to the bottom of the pot.
Add the kale and mix well. Cover and cook for about 2 minutes, stirring frequently to prevent sticking and cook all the kale evenly. Add a sprinkle of water if needed.
Lay a tortilla in a flat pan over medium high heat. Put 1/2 to 1/4 cup of the filling and a large pinch of cheese on half of the tortilla and fold in half.
Cook a few minutes on that side, until the tortilla is crispy, but not burned. Flip to the other side and cook again until that side is crispy as well. Top with salsa if you like.
This recipe makes 10-12 quesadillas. If you want to serve a smaller crowd, make as many individual quesadillas as you like, and store the leftover fillings in the refrigerator for up to 5 days.