Marinate the Beef: In a bowl, combine the beef strips with 2 tablespoons of soy sauce and 1 tablespoon of cornstarch. Toss until the beef is evenly coated and set aside to marinate for 15 minutes.

Prepare the Sauce: In a small bowl, mix the remaining 4 tablespoons of soy sauce, ½ cup water, oyster sauce, Shaoxing wine, sugar, and pepper. Stir until the sugar dissolves and set aside.

Cook the Beef: Heat 2 tablespoons of canola oil in a large skillet or wok over medium-high heat. Add the beef and stir-fry for 2-3 minutes until lightly browned. Remove from the skillet and set aside.

Cook the Vegetables: Add the remaining 1 tablespoon of oil to the skillet. Stir-fry the garlic and onions for about 30 seconds, then add the red bell pepper, baby corn, snow peas, and water chestnuts. Stir-fry for 3-4 minutes until the vegetables are tender-crisp.

Combine and Finish: Return the beef to the skillet. Pour in the prepared sauce and stir well to coat all the ingredients. Cook for another 2-3 minutes, allowing the sauce to thicken slightly.

Serve: Remove from heat and serve hot over steamed rice or noodles. Garnish with green onions or sesame seeds if desired.