Mix the fajita seasoning with the oil in a shallow bowl, add the meat and rub all over
Cover the bowl with cling film and place in the fridge to marinade for at least a couple of hours
When your barbecue has been lit and the coals are covered with ash, push some of the coals to one side. This is what allows the chicken to cook more slowly, ensuring it’s safely cooked through and still succulent and juicy.
Shake off the meat to remove the excess oil and place on the grill, to the side of the area you cleared of coals. Turn regularly until cooked through – it should take up to 25 minutes depending on your barbecue but as this is chicken, you need to be absolutely sure it’s safely cooked through before serving – you’re looking for clear juices and absolutely no pink bits. If you have a meat thermometer, aim for a core temp of 75C/165F.
When cooked, transfer the meat to a plate and leave to rest while you prepare the remainder of the dish
Warm the tortillas briefly on the barbecue to soften
Fold each tortilla in your hand to create a soft C shape. If you want to keep them together before your guests arrive, you can line them up in a roasting tin as you work
Fill with shredded lettuce and diced tomatoes
Thinly slice the rested chicken and line on top of the salad