If you have a searing function on your slow cooker, cook the chicken for around 5 mins, turning occasionally until browned. If you do not have a sear function, cook in a pan & then transfer to the slow cooker.
Combine sugar, garlic, ginger, soy sauces, vinegar, honey & sesame oil in a bowl & pour over chicken.
Turn the chicken to coat.
Cook on low for 5hrs.
Remove chicken from the slow cooker & shred.
Combine the cornflour & water in a small bowl & add to sauce in slow cooker. Mix well.
Cook on high setting for around 10 mins or until sauce thickens.
Add chicken back to slow cooker & stir into sauce. Cook for a few minutes until chicken is fully combined with the sauce.
Add chopped spring onion once served.