Clean and trim the chicken.
Put the chicken into a sauce pan and cover with water. Salt generously. Bring to a boil and then simmer for 10-15 minutes.
Let cool, and then shred.
Mix up the mayo, Hoisin, vinegar, hot sauce, horseradish, sesame oil, onion whites, garlic, salt and pepper. Taste and adjust for seasoning.
Put a few spoonfuls of the sauce into the bottom of the slow cooker.
Place the chicken in the slow cooker.
Pour the remainder of the sauce over the chicken.
Place the lid on the slow cooker and cook on low for 4 hours.
Serve on buns or in egg rolls.