In a medium mixing bowl, add ground beef and marinade ingredients. Hand mix until ingredients are incorporated. Marinate for 10-15 minutes.
In a small bowl, combine the sauce ingredients and set aside.
Meanwhile, in a wok or large frying pan on medium high heat, add 1 tablespoon vegetable or canola oil. Add ground beef, let it sear for 1 minute and flip over. Sear for another minute before breaking it up and stir fry for about 3-5 minutes, until cooked through. Remove and set aside.
Add the onions and zucchini and cook for 3-5 minutes until tender. Add garlic and cook for another 30 seconds, until fragrant. Add beef and juices. Stir all the ingredients together and cook for another minute.
Push the mixture to the sides and add sauce. Meanwhile, in a small bowl, dissolve cornstarch in cool water to make a slurry. Once the sauce is bubbling, stir in the slurry and cook until the sauce starts to simmer and thicken.
Sprinkle ground white pepper and drizzle sesame oil over top.
Serve over rice.