Heat oil in 3-qt. pot over medium heat. Add chipotles and cumin; season with salt, if desired. Cook 1 minute, or until fragrant. Stir in onion, bell pepper, and garlic. Sauté 5 to 7 minutes, or until vegetables are soft. Stir in beans, beer, tomatoes, and corn. Bring chili to a boil. Reduce heat to medium-low, and simmer, uncovered, 45 minutes, or until thick.