If you’re using dried beans, soak them overnight in a saucepan of cold water. The next day, drain them, rinse well and return to the pan. Cover with water, bring to the boil and simmer for 1 hour. Skim off any froth that rises to the top during cooking. Drain and cool.
Cook the potatoes in their skins in a pan of simmering water for 20 minutes. Drain and allow to cool, then cut into wedges. Dip the tomatoes in a pan of boiling water for 20 seconds, peel, cut into wedges and remove the seeds. Mix the potatoes, tomatoes and drained beans together.
Combine the spring onions, parsley and chilli with the olive oil, lemon juice, zest and seasoning. Pour over the tomatoes, beans and potatoes, mix well and serve immediately.