In a large bowl, combine egg white, vinegar, cornstarch, and salt until smooth. Add sliced chicken, ensuring it is well coated. Cover with plastic wrap and refrigerate for 30 minutes to marinate.
In a pot over high heat, bring water and oil to a boil. Then, reduce heat to medium.
Remove the chicken from the marinade, shaking off excess. Discard the marinade. Quickly boil the chicken until the outside turns white, around 1 minute, ensuring it's not fully cooked through.
Cook chicken in a hot oiled wok or skillet until fully cooked and juices run clear, or refrigerate parboiled chicken in a sealed container for a few hours.