Place the beef in a shallow dish and squeeze the juice from the limes over the beef and then season both sides with the taco seasoning. Let marinate for at least an hour, ideally overnight.
Turn on the grill.
Slice the veggies and prepare the toppings.
Grill the beef for 6 to 8 minutes, per side, until cooked through. Cooking time may vary depending on heat over the grill and thickness of the beef.
Grill the veggies alongside the beef in a grill basket, or in a "foil basket." (Use a piece of foil and make a 'basket' for the peppers and onions.
Slice the beef across the grain once it has cooked.
Add beef, peppers and onions and toppings to the tortillas.
Prepare fresh fruit.
Serve Grilled Beef Fajitas with fresh fruit.