In a bowl mix the rice wine vinegar, soy sauce, sesame oil, marmalade, brown sugar, salt and pepper. Set aside.
In a ziplock bag, add the cornstarch and chicken. Shake to coat. Pour vegetable oil in the skillet and brown the sides of the covered chicken. The chicken doesn't need to be fully cooked since it is going in the crockpot.
After the chicken is done cooking, pour the pieces into the crockpot. Then cover the chicken with the sauce mixture and give the pot a stir.