Rub the 1 tablespoon oil over the squash slices. Heat a griddle pan until smoking hot, add the squash slices in batches and cook for 7–10 minutes, turning once, until lightly charred and just cooked through. Leave to cool.
Make the dressing by mixing together the coriander, chilli, lime rind and a little of the lime juice in a bowl. Stir in the oil, then add more lime juice if needed and season well.
Arrange the spinach leaves and cooled squash on a serving plate. Drizzle over the dressing, then scatter with the feta and pumpkin seeds and serve.