Heat the oil in large skillet over moderate heat. Add the garlic, onion, and bell pepper, cover and cook, stirring occasionally until the vegetables are soft, about 10 minutes.
Add the cumin and cook, stirring, for 1 minute.
Add the ground beef; raise the heat to high and cook, breaking up the meat with a spoon, until the meat is no longer pink.
Transfer mixture to slow cooker.
Stir in beans, tomatoes, water, chipotle, oregano, salt and pepper.
Cook on low for 4 hours or high for 2 hours. (or until desired consistency)
Season to taste with salt and pepper.
Top with cheese, sour cream and crackers.**optional