Place chicken breast, onions, and garlic into the slow cooker.
In a small bowl, combine coconut animos, honey, ginger, vinegar, and pepper.
Pour mixture over chicken, and turn the chicken to make sure it's coated in sauce.
Place lid on top, cook on low for 8 hours or high for 5 hours.
Remove chicken from the slow cooker and use 2 forks to shred. Set aside.
In a small bowl, mix the arrowroot powder and water.
Pour mixture into sauce in slow cooker, cover, and cook on high for 30 minutes*. The sauce will thicken up. **Alternatively, if you don't want to wait 30 minutes for the sauce to thicken, you can pour the sauce into a small saucepan and then add the arrowroot mixture, bring to a boil and then simmer a few minutes. This will thicken up the sauce in 5 minutes or less.
Once the sauce has thickened, return chicken to slow cooker and stir to coat.
Serve in lettuce cups with a dash of sesame seeds on top.