Cut the chicken into very small pieces.
Sprinkle with pepper and a couple teaspoons of soy sauce.
Cook in batches in a large skillet until done.
Put all the chicken back into the skillet.
Add the garlic, green onions, and water chestnuts.
Stir soy sauce, vinegar, cayenne, sugar and cornstarch together.
Pour into the skillet and cook till hot and bubbly.
Serve right away in slices of lettuce or over rice.
To freezer, cool and put in zip top freezer bag. Thaw in the refrigerator and reheat in the microwave.