Preheat oven to 200°C/400°F/gas mark 6. Scrub potatoes, cut into wedges and put in a bowl. Add sunflower oil, season with salt and freshly ground black pepper and toss. Put in a roasting tin and bake for 35 mins, turning once or twice.
Meanwhile, put mushrooms into a shallow dish. Combine olive oil, pesto and crushed chillies. Pour over mushrooms and set aside.
10 mins before chips are ready, fry mushrooms for 5-10 mins, turning halfway. Top each ciabatta half with tomato slices, a few salad leaves and a mushroom. Serve with the chunky chips.