Stir-fry beef in pan with 2 teaspoons of oil over medium-high heat for 2 minutes or until browned. Remove beef with tongs or fork, allowing excess oil to drip off and set aside.
With remaining oil, stir-fry ginger and garlic for 2 to 3 minutes and then add bell peppers.
Cook another 2 to 3 minutes.
Mix together fresh arugula and bell pepper mixture in a serving bowl. In a small bowl, combine kuzu, tamari, vinegar and water.
Place mixture into skillet and cook over medium heat until sauce starts to thicken.
Return beef to skillet and cook for 1 minute, just enough to warm up beef.
Add beef to serving bowl with arugula and bell peppers.
Mix and serve warm.
Recipe by Health & Nutrition Coaching at http://healthandnutritioncoaching.com/beef-and-arugula-stir-fry/