To make the salsa, drain the sweetcorn and trim the spring onions. Place a large non-stick frying pan over a high heat and cook the whole pepper, tomatoes, spring onions and chilli (if using) for 10 minutes, turning occasionally, until soft and charred.
Place the peppers and chilli (if using) in a bowl, cover with a plate and set aside for 5 minutes. Remove the tomatoes and spring onions to a board to cool. Add the drained sweetcorn to the pan and cook for 1 minute to get a little charred, too.
Once cool enough to handle, roughly chop the tomatoes and spring onions and place them in a separate bowl with the charred sweetcorn. Peel, deseed and roughly chop the pepper and chilli (if using). Pick and roughly chop a few coriander leaves (if using) then add it all to the bowl. Mix in a good squeeze of lime juice, a small drizzle of oil and season with a small pinch of salt.
To make the tortilla chips, stack the tortillas on top of one another and cut them into eighths. Arrange the pieces over two large 40cm x 30cm baking trays in one layer, then bake in the oven for 15 minutes, turning halfway, until golden on both sides.
Meanwhile, drain and rinse the beans, then blot dry with kitchen paper. Tip them into the frying pan over a medium heat and leave for 5 minutes, shaking the pan occasionally – you want them to char and pop open, bursting their skins.
Peel, destone and slice the avocado into chunks, then drizzle with the remaining lime juice.
Remove the tortillas from the oven, leave to cool slightly, then arrange in a shallow bowl or platter. Top with the popped beans, tomato and pepper salsa and the dressed avocado. Crumble over the feta and pick over the remaining coriander leaves (if using), then tuck in!
