Bring a large pot of salted water to a boil. Stir in pasta and return pot to boil. Cook until al dente. Drain well.
Place squash and zucchini in a medium saucepan with 2 cups of water. Bring to a boil and cook until tender, about 15 minutes. Drain and set aside.
In a large bowl, combine pasta, squash, zucchini, kidney beans, corn and tuna. Mix well and chill for at least 30 minutes. After salad is chilled, stir in dressing and serve.
