This is truly the best beef stir fry! It's a healthy meal that includes thin slices of sirloin steak and zucchini. A delicious entree for the whole family and ready in about 20 minutes!
Heat 1 tbsp of oil in a large skillet on medium-high heat. (I recommend a 12" skillet so you have room for everything.) Once oil is hot, add your thinly sliced steak pieces. Cook until steak is browned, stirring frequently, about 2 to 3 minutes. The steak doesn't need to be completely cooked through. Remove steak from pan and set aside. (Leave any remaining liquid in the skillet to cook our veggies in.)
Reduce heat to medium. Add remaining 1½ tablespoons of oil to skillet with the zucchini and onion. Sprinkle with salt, pepper, ginger, and garlic powder. Stir. Sauté, stirring occasionally, until the onion is translucent and zucchini is tender, about 7 to 10 minutes.
Add rice vinegar and coconut aminos to the skillet with vegetables. Return your steak to the skillet. Stir and cook until steak and sauce have warmed, about 2 to 3 minutes. Garnish finished stir fry with sliced green onion or sesame seeds if desired.