Combine sauce ingredients in a small bowl. Set aside.
Cook beef in a large skillet with garlic and ginger until no pink remains. Drain any fat and place beef in a small bowl to keep warm.
Heat oil in the pan. Add onion, celery, and cabbage and cook 3-4 minutes or until it begins to soften. Add peppers and cook 2-3 minutes more.
Add beef, water chestnuts, and sauce back into the pan. Stir to combine. Allow sauce to come to a simmer and thicken.
Serve over rice and garnish with sesame seeds and green onions if desired.
