Mix the soy sauce, honey, rice wine vinegar, onion, garlic, pepper and ground ginger together in a small bowl and set aside.
Oil the slow cooker and add the chicken breasts. Pour the sauce over the chicken, cover and cook on high for 3 hours or low for 5-6 hours.
Remove and drain the chicken and set aside in a large bowl. Shred thoroughly with two forks.
Transfer the leftover sauce into a saucepan and add (cold) water mixed with the cornflour. Reduce over a medium heat until thick.
Add the chicken, carrots, water chestnuts - maybe some other veggies to the sauce and mix thoroughly. Serve over a bed of rice with cut green onions and sesame seeds.