Preheat a grill pan over medium heat. Cook corn, turning, 15 minutes or until tender and lightly charred. Cool slightly; cut kernels from cobs. Transfer to a medium bowl.

Meanwhile, make tomato salsa.

Preheat oven to 220°C (200°C fan-forced).

Mash beans in a medium bowl to crush slightly. Stir in coriander, corn, half the pepitas, half the cheddar and half the feta; season with black pepper.

Divide filling between tortillas, placing it over half of each tortilla, leaving a 1cm (½-inch) border. Fold tortillas over to enclose filling, pressing down firmly. Place on baking-paperlined oven trays. Brush tops with oil. Scatter with combined remaining cheeses and pepitas.

Bake quesadillas 15 minutes, swapping trays from top to bottom, for even browning, or until browned lightly and filling is hot. Serve with salsa and sour cream.

Quarter tomatoes. Squeeze out seeds; finely chop. Combine tomato with remaining ingredients in a small bowl; season to taste. You can substitute either one fresh red bird's-eye chilli or ½ teaspoon chilli flakes for pickled jalapeño if you like. For a lower fat version, use reduced-fat cheeses and sour cream.