Prep: 1. Preheat oven to 350 and grease a 9x9 baking dish (preferably with a lid). 2. Grate cheese and chop cilantro. Make: 1. Slice polenta and place in the bottom of the dish. 2. Place beans, liquid and all, into a large bowl and mash (if they seem super liquidy drain a little). 3. Add corn, salsa, oregano, cumin and salt to beans and mix thoroughly. 4. Pour bean mixture over polenta. 5. Sprinkle with cheese and cilantro. 6. Cover and bake for 15 minutes, then uncover and continue to bake for another 15. 7. Let cool slightly before serving.