Scrub and prick the sweet potato all over with a fork and cook in the microwave on full power (800W) for 10 minutes, or until cooked through. Meanwhile, trim the spring onions, slice off the green tops and set aside for later. Deseed and quarter the pepper, peel and finely slice 2 cloves of garlic. Put 1 whole spring onion and 1 piece of pepper aside for later, then blister and char the rest in a large dry non-stick frying pan on a medium-high heat, adding the frozen sweetcorn after 2 minutes. Add the garlic, 1 tablespoon of olive oil and the smoked paprika, tossing regularly. Once the garlic is golden, remove the contents of the pan to a board and quickly wipe out the pan. Drain the black beans (saving a splash of juice for later), then tip them into the dry hot pan and leave them to pop and go crispy, it should take about 5 minutes. Roughly chop the sweet potato and add to the charred veg, chopping and mixing as you go. Drizzle over 1 tablespoon of oil and mix in most of the popped beans (saving a small handful for later), then season to perfection with sea salt and black pepper. Divide the filling between the tortillas, then roll up into thin cigars, placing into an oiled snug-fitting baking dish (roughly 30cm x 20cm), with the scruffy ends tucked underneath. Preheat the grill to high. Peel and finely grate the remaining garlic clove into a bowl, tip in the tomatoes, add a small pinch of salt and pepper and use a fork to mix it up, squashing the tomatoes to create a simple sauce. Pour it over the tortillas, along with a splash of the reserved bean juice. Finely grate over the cheese and grill for 5 minutes, or until golden and crispy. Meanwhile, finely slice the reserved green spring onion, finely slice the pepper and place in a bowl. Season with a small pinch of salt and pepper, add 1 teaspoon of red wine vinegar and toss together with the reserved crispy beans. Ripple a good few shakes of chilli sauce through the yoghurt. Serve the enchiladas with the salsa and a dollop of yoghurt – delicious!