Combine the orange juice, lime juice, apple cider vinegar, avocado oil, garlic, herbs, and spices and mix well to combine.
Add the marinade to a large bag or a deep bowl and add the flank steak, making sure that the steak is fully covered in the marinade. Place in the fridge for at least 2-3 hours. Remove the steak from the marinade and allow it to come to room temperature.
Prepare the grill (or grill pan) by setting to medium-high heat. Coat lightly with avocado oil.
Once the grill is hot, add the flank steak to the grill and grill for about 5-8 minutes on each side. The internal temperature should read 145-155F for a medium steak.
Remove from the grill and allow to rest for 10 minutes before slicing very thin against the grain.
Serve as tacos, or burrito bowls!
Notes
All nutrition facts are estimations and will vary. Nutrition facts do not include optional/'to serve' ingredients.