Combine the marinade ingredients in a medium bowl and add the steak. Marinate for at least 1 hour, but up to a couple days. If marinating for only an hour you can keep it on the counter, otherwise keep it covered in the fridge.
Make the sauce. In a small bowl, combine coconut aminos and arrowroot powder and stir until combined. Set aside.
Once ready to cook, add avocado oil to a large skillet and heat over medium heat. Add in the peppers and cook for 7 minutes.
Add the beef (and marinade) and cook for 5 minutes, stirring regularly. Add int he sauce and cook 3 minutes until thickened. Serve warm and store leftovers in the fridge.