Cook the pasta according to the package directions.
Meanwhile, place the potatoes and salt in a large saucepan. Add enough cold water to cover. Bring to a boil. Reduce heat and simmer until the potatoes are almost but not quite tender, about 15 minutes. Add the beans and cook until tender, about 5 minutes. Drain the potatoes and green beans in a colander. Let cool slightly. Cut the potatoes into a 1/2-inch dice and cut the green beans into 1-inch pieces.
Place the pasta in a large bowl and add the potatoes, green beans, pesto, Parmesan, and pine nuts (if using). Toss to combine.
Tip: There's no need to peel thin-skinned potatoes like Yukon golds. But be sure to scrub them.