In a large slow cooker, add sliced onion and top with chicken.
In a small bowl, add 1 cup of the wing sauce, the garlic and cumin and stir to combine. Pour over chicken.
Cover and cook on low for about 5 hours, or until the chicken is cooked and can be shredded.
When done, remove chicken and shred with two forks and place back into crockpot.
Mix chicken with sauce in crockpot and cover. Let cook an additional hour to allow the chicken to soak up the sauce.
Serve on rolls. Toast rolls in oven if desired before filling with buffalo chicken. Also, you can top the chicken with coleslaw for a crunch.