To Marinate: Place chicken in a nonporous glass dish or bowl. In a small bowl mix together oyster sauce, sesame oil, sugar, egg, salt and pepper; pour mixture over chicken, cover dish and marinate for at least 1 hour.
Dip marinated chicken in cornflour and sautee in a large skillet until cooked through (juices run clear) and color is a nice, golden brown.
To Make Sauce: Bring 1/2 cup water to boil in a small saucepan; dissolve sugar in boiling water, then add lemon juice and thicken liquid with pudding mix.
Cut chicken into bite size pieces and pour sauce over all; sprinkle with toasted sesame seeds and serve.
