1. Preheat oven to 400°.
2. Cut each tortilla into 6 wedges. Arrange wedges in a single layer on a large baking sheet coated with cooking spray. Sprinkle with salt. Bake at 400° for 10 minutes or until golden brown and crisp, stirring occasionally.
3. Heat oil in a medium saucepan over medium heat. Add onion to pan; cook 8 minutes or until tender, stirring occasionally. Add cumin and garlic; cook 1 minute. Add oregano and beans; bring to a boil. Mash with a potato masher. Reduce heat, and simmer 10 minutes or until thickened, stirring occasionally.
4. Spoon bean mixture into a 3-cup gratin dish coated with cooking spray. Top with cheeses. Bake at 400° for 12 minutes or until hot and bubbly.
5. Combine tomatoes and chile in a mini food processor; process until smooth. Spoon tomato mixture over bean mixture. Sprinkle with cilantro.