Using a sharp knife, score the skin of a 1.4kg pork shoulder. In a small bowl, combine 1 tbsp smoked paprika, 1 tbsp ground cumin, 2 tsp chilli powder, some salt and black pepper and 1 tbsp olive oil. Rub all over the pork. Place 1 sliced onion and 3 sliced garlic cloves in the base of a slow cooker and place the pork on top. Pour in 50ml apple juice, 250ml chicken stock and 2 tbsp of the liquid from a jar of pickled jalapeños. Cover and cook on low for eight hours or on high for four until the meat is falling apart. Transfer the pork to a chopping board and use two forks to shred the meat. Discard the skin and as much fat as desired. Place the pork in a bowl. Pour over some of the juices from the slow cooker and toss to coat. Preheat the oven to 220˚C/200˚C fan/gas mark 7. Spread 1 x 180g bag of tortilla chips on a large rimmed baking tray. Layer over as much of the pulled pork as you like, reserving the remainder for another meal. Add some thinly sliced red onion, a generous handful of grated Mozzarella and some pickled jalapeños. Drizzle over some barbecue sauce and bake in the top half of the oven for 5-6 minutes until the cheese is melted. Top with shredded Little Gem lettuce and/or chopped tomato, if desired.