In a small bowl, mix together the mayonnaise, chilli flakes, oregano and garlic. Season with freshly ground black pepper and spread over the chicken.Cover with cling film and leave to marinate in the fridge for an hour, or longer if you have time.
Finely chop the cherry tomatoes and avocado. Stir through the sweetcorn and the rest of the mayonnaise. Season with black pepper and the lime juice.
Once marinated, BBQ the chicken over a medium heat for about 15 minutes, turning frequently until the chicken is cooked through with no pink showing. Remove from the heat and allow to cool for a few minutes before chopping roughly and stirring through the quesadilla mixture.
Spread the mixture evenly across half of each tortilla, sprinkle with grated Cheddar and fold over the empty half of the tortilla to create a half circle, pressing down firmly.
Lay the quesadillas over the BBQ and grill over a medium heat for 2-3 minutes on each side, or until the cheese has melted and the tortillas are crisp. Cut into wedges and serve immediately.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.