Blend orange juice into cornstarch; stir in soy, sugar, and lemon juice. Set aside.
Drain peaches; reserve syrup for another use.
Add cooking oil; preheat wok over high heat.
Stir-fry peanuts 2 to 3 minutes or till toasted; remove from wok.
Stir-fry gingerroot 30 seconds.
Add onion; stir-fry 2 minutes.
Add zucchini; stir-fry 1 minute.
Remove vegetables from wok; add more oil if needed.
Stir-fry ham in hot oil 2 minutes.
Stir orange juice mixture; add to wok. Cook and stir till thickened and bubbly; cook and stir 2 minutes more.
Stir in peaches, peanuts, and vegetables; cover and cook 1 to 2 minutes.
Serve over rice sticks if desired.