Wash and finely chop the onion, capsicum, tomato (deseeded), and coriander leaves.
In a bowl, mix the chopped veggies with mayonnaise, ketchup, chili flakes, grated cheese, and coriander until evenly combined.
Trim the bread edges and roll each slice thin and flat with a rolling pin.
Place 1 to 2 tablespoons of filling in the center of each slice, roll up, seal the edge, and secure with a toothpick.
Brush the rolls all over with melted butter.
Preheat the air fryer to 180°C (360°F) for 3 to 5 minutes.
Air fry the rolls at 180°C (360°F) for 8 to 10 minutes, flipping once, until golden and crisp.
Remove the toothpicks and serve hot with ketchup or chutney.