Heat coconut oil over medium high heat. Add steak. Cook, stirring frequently, 2-3 minutes. Remove from pan and keep warm.
In same pan, add carrots and red pepper. Stir fry 2 minutes, stirring frequently. Add mushrooms, zucchini, and peapods. Stir fry another 2-4 minutes. Return beef to pan.
Pour sauce (without cornstarch) over veggies and beef in pan, and then stir in cornstarch mix. Heat, stirring constantly, until sauce thickens, about 1 minute. Remove from heat and sprinkle with green onions and sesame seeds.