Heat 1 tbsp olive oil in a large skillet over medium-high heat.
Add sliced steak and cook until browned, about 3-4 minutes. Remove from skillet and set aside.
In the same skillet, add remaining olive oil and sauté bell pepper, zucchini, and broccoli until tender-crisp, about 5 minutes.
Return steak to the skillet.
In a bowl, whisk tamari, honey, rice vinegar, cornstarch, and water. Pour sauce over beef and vegetables.
Stir and cook until sauce thickens slightly, about 2 minutes. Serve warm.