Haricots verts are thin, tender green beans. If you can't find them, use trimmed regular green beans, but add them to the pasta after 8 minutes of cooking since they'll take longer to cook. You can make the salad ahead, but dress it just before serving so the beans don't turn drab.
I came up with the recipe for the lemonade first and then discovered that it went amazingly with gin, making it a favorite summer drink in our house! - piccantedolce