Lay out 4 tortillas. In a small bowl, mix spring onion, avocado, juice, chilli sauce and fresh coriander or parsley. Spread over the tortillas like buttering bread. Season with salt and freshly ground black pepper. Sprinkle over with cheese and cover each with another tortilla.
Heat oil in a large, preferably non stick, frypan. Add a tortilla sandwich. Fry for 2 minutes each side. Keep warm in the oven while you cook the remainder, oiling the pan lightly between each one. Cut into wedges. This is easily done with kitchen scissors.