Saute the onion and the garlic in the oil then stir in the chili powder and the cumin. Stir in the chicken and let cool, meanwhile heat oven to 450 and grease a rimmed baking pan. Spoon a Tablespoon of beans down the center of each tortilla and top with scant 1/2 cup of chicken mix. Fold the top and the bottom down on the tortillas and then roll to close. Place in baking pan, seam side down and brush with oil. Bake 20-25 minutes, turning every 5 minutes or so. Serve with desired toppings such as sour cream and/or guacamole.