In a medium bowl, combine the marinade ingredients: soy sauce, ginger, and garlic. Add thinly sliced chicken breast, ensuring it's well-coated. Marinate for at least 30 minutes in the refrigerator.

Mix the sauce ingredients in a small bowl, whisking until the cornstarch fully dissolves. Set aside.

Heat a tablespoon of oil in a wok or large pan over high heat. Add the marinated chicken in a single layer, cooking for about 3-4 minutes on each side until golden brown and cooked through. Remove and set aside.

In the same pan, sauté sliced mushrooms and zucchini for 2-3 minutes until tender-crisp.

Return the chicken to the pan, pour in the prepared sauce, and stir to coat. Cook for an additional 1-2 minutes until the sauce thickens.