Bring a medium pot of salted water to a boil over high heat. Add the green beans and stir. Cook for about 2 minutes, or until beans are slightly tender. Transfer the cooked green beans to a bowl of ice water and let cool for 3 minutes. Drain the green beans.
In a large bowl, combine the green beans with the lettuce, cannellini beans, olives, and red onion. Toss to combine. Drizzle with lemon juice and olive oil. Sprinkle with salt and pepper and toss to coat. Top with shaved Parmesan and serve.