Whisk together oil, lemon juice, lime juice, orange juice, garlic, chili powder, and salt. Pour into a large ziploc bag.
Add steak to the bag, press out all of the excess air, and seal the bag.
Chill for 30 minutes.
Use tongs to transfer steak to a preheated grill or grill pan, discard excess marinade.
Grill for about 8 minutes on each side or until cooked to desired doneness. (I like mine just a little pink in the middle for best flavor and ultra juicy/tender steak).
Assemble tacos with steak in the tortillas, topped with your favorite garnishes like avocado, onions, cilantro, salsa, and fresh squeezed lime juice.