Heat the oven to 180°C/Fan 160°C/Gas 4. Cut the wraps into triangles. Lay them in a single layer on 1 or 2 baking trays. Slide into the oven and cook for 5-8 mins till crisp and golden. Leave to cool. Turn the oven down to its lowest temperature
Halve the tomatoes. Zest the lime and juice half. Set the zest aside. Put the lime juice in a bowl. Peel and finely slice the onion. Add to the lime juice with a pinch of salt. Scrunch together. Peel and coarsely grate the carrot. Add to the limey onion. Finely chop the coriander stalks and add to the carrot, then set aside to pickle. Set the coriander leaves to one side.
Cut the lime half into wedges. Peel and grate the garlic into a medium bowl. Add 2 tsp cumin and ½ tbsp oil. Stir to make a paste. Add the beef to the bowl with some seasoning. Toss to thoroughly coat the beef.
Cut a little bit of the chilli and taste it to check for spiciness. Finely chop it and stir as much you like (or dare!) through the crème fraîche. Add a pinch of salt and a crack of black pepper
Heat a frying pan till smoking hot. Throw in the beef strips and cook for 2 mins, stirring till browned. Remove from the pan and cover with foil. Place in the oven to keep warm.
Place the pan back on the heat. Add in the halved tomatoes with a pinch of salt (no oil needed). Cook for 3-4 mins till slightly charred and deflated. Pour in 100ml boiling water. Cook for a further 4 mins till the liquid has almost evaporated and you have a chunky tomatoey sauce.
Place the tortilla crisps onto a large platter. Spoon over the tomatoes. Scatter over the carrot and onion. Finish with the beef. Drizzle over the chilli crème fraîche and sprinkle with coriander leaves and lime zest. Squeeze over wedges of lime and serve with handfuls of the peppery salad leaves.