Preheat the oven to 190°C, fan 170°C, gas mark 5. Place the potatoes on a baking tray, drizzle with some olive oil and season. Bake for 45 minutes until brown and crisp.
Meanwhile, in a large saucepan, heat 1 teaspoon of the olive oil and fry the onion, until soft. Add the chilli powder and the mince, and cook until the mince is browned.
Add the stock to the pan along with the peeled tomatoes and the drained red kidney beans, then simmer on a low heat for 20 minutes.
Serve with the potato wedges and the lettuce leaves.