Pour the tomatoes in a large pan and add one can of cold water. Season with pepper only at this stage and bring to the boil. Reduce to a simmer, and add the shredded cavolo/cabbage/kale to the pan. Partially cover and simmer for about 15 minutes until the greens are tender. Add the beans and simmer for a few minutes to warm the beans through. Season with salt and any more pepper to taste. Serve with a drizzle of olive oil.