Wash and slice the courgette lengthways then cut each half in 1cm slices. Slice the onion and pepper into 1cm strips. Wash and finely dice the tomato and set aside.
Heat a frying pan with the oil, add the onion, pepper and courgette, a pinch of salt and pepper and cook for 8 minutes until tender.
Prepare the tortilla according to the packet instructions then place onto a plate and add the vegetables. Sprinkle with the diced tomato and the tzatziki and roll.