Heat grill to medium-high. Put 2 tortillas onto a large baking sheet, then grill for 2 mins. In a bowl, mix the refried beans, cayenne pepper, kidney beans and cherry tomatoes, then divide half the mix between the tortillas. Scatter with half of the cheese and half of the sliced chilli, then grill again until the cheese melts. Lift onto plates and top with half of the avocado and coriander to serve. Repeat with the remaining tortillas.