Marinade: Mix together the taco seasoning, lime juice and vegetable oil. Stir until fully blended and the seasoning has dissolved. Place the meat into a plastic storage bag and pour the marinade on top. Shake making sure the marinade covers all sides of the meat. Marinate for at least 4 hours, preferably overnight.
Mix together all ingredients for the crema, cover and chill thoroughly.
To grill the steak: Remove the steak from the plastic bag and discard the marinade.
Grill the steaks on medium-high heat for 3-5 minutes on each side or to your desired level of doneness.
Rest covered loosely with aluminum foil for 5 minutes before slicing thinly across the grain.
Serve with warm grilled tortillas or crispy taco shells and assorted toppings of your choice.
Serve with a generous drizzle of cilantro-lime crema.
Crema has a milder taste compared to sour cream. It's found alongside the speciality Mexican cheeses in the dairy section of most grocery stores. If you can't find it, sour cream always works.