Place garlic, onion, soy sauce, honey, rice wine vinegar, ginger and pepper into the base of the slow cooker. Stir well to combine.
Place chicken breast fillets into the sauce and turn to coat well. Place the lid on and cook for 4-6 hours on high or 6-8 hours on low.
Remove chicken breast from the slow cooker. Shred the hot chicken with two forks.
Mix the water and cornflour together and stir into the sauce in the slow cooker. Turn the slow cooker to high and bring the sauce to the boil and cook for 3 minutes. Return shredded chicken intto the slow cooker when the sauce is ready. Serve with rice and garnish with shallots and sesame seeds.