Heat the olive oil in a pot over medium heat. Add the leeks and sauté for 6 to 8 minutes until soft. Pour the tomatoes into a pot and add 2 cans of water. Season with salt and pepper and bring to a boil, then reduce the heat to a simmer. Roughly shred the kale leaves and add them to the soup. Partially cover the pot and simmer gently for 15 minutes or until the kale is tender. Add the cannellini beans to the pot and heat through for 5 minutes. Adjust the seasoning to taste by adding salt and pepper. Ladle the soup into bowls and drizzle with a little olive oil and top with Parmesan cheese.