First make the salsa: chop the tomatoes, onion and coriander leaves. Combine these in a bowl. Add the minced garlic and half of the chilli (if used). Drizzle with oil and freshly squeezed lime. Season with salt and freshly ground black pepper. Cover and rest.
Shred or thinly slice the chicken. Thinly slice the onion, garlic, chilli (if used) and bell pepper.
Heat the oil in a large wok or non-stick frying pan, add the onion and peppers and stir-fry for 5 minutes. Add the chicken, garlic, chilli, paprika, cumin and oregano and cook for another 5 minutes, or until the chicken is cooked/warmed through. Add the corn and coriander leaves- squeeze some lime juice over it. Warm through.
Meanwhile warm the tortilla in a heated pancake or griddle pan. This should only take a minute or so.
Spoon some of the chicken mixture into the centre of each tortilla, add a couple spoonful of salsa. Roll up and serve warm.