Prepare Chili: In a large saucepan, cook onion, bell pepper, garlic, chili powder, cumin, and cayenne (if desired) over medium heat for 5-7 minutes, stirring occasionally. Add jalapeno, salsa, beans, and tomatoes, and stir to combine.
Meanwhile, season the beef with the barbecue seasoning.
Transfer chili to a 5-quart slow cooker. Add the beef and turn to coat.
Cover and cook on LOW for 7 to 8 hours (or on HIGH for 3 to 4 hours) or until the beef is fork-tender.
Transfer the beef to a cutting board and let stand for 10 minutes. Using 2 forks, shred the beef. Return shredded beef to the slow cooker and stir to coat.
Divide the beef and chili mixture among the buns and sprinkle with shredded cheese. Serve.
Chili recipe adapted from American Heart Association