Nonstick cooking spray
1 tablespoon olive, vegetable, or canola oil
1 medium onion, chopped small
1 clove garlic, minced
1 fresh chile pepper, chopped small (optional)
1 teaspoon ground cumin
1 1/2 teaspoons chili powder (adjusted to taste)
1 can (14 ounces) or 1 1/2 cups chopped tomatoes, drained, with 1/3 cup juice reserved
1/4 cup tomato paste
2 cans (15.5 ounces each) black, red or kidney beans (or a mixture of any two), drained and rinsed
Kosher or coarse salt and freshly ground black pepper
1 1/2 cups corn kernels, fresh (from 1 to 2 ears), from 1 15-ounce can, drained, or frozen and thawed
3 cups (about 2 3/4 ounces) rough-chopped spinach leaves
6 medium-size (8-inch) flour tortillas (although corn should work too)
2 cups (8 ounces) shredded Monterey Jack or cheddar cheese (I used a mix)
Chopped fresh cilantro, sour cream and/or salsa for serving (optional)