Green Bean and Pasta Salad

4 ounces penne (1 1/4 cups)
4 ounces green beans, halved crosswise (about 1 cup)
1 cup canned red or kidney beans, rinsed
1/4 cup chopped fresh flat-leaf parsley
2 tablespoons grated Parmesan (2 ounces)
2 tablespoons olive oil
2 tablespoons fresh lemon juice
kosher salt and black pepper

Cook the pasta according to the package directions, adding the green beans during the last 3 minutes of cooking. Drain and run under cold water to cool.
Toss the cooled pasta and green beans with the red beans, parsley, Parmesan, olive oil, lemon juice, ½ teaspoon kosher salt, and ¼ teaspoon black pepper. Divide the salad between 2 containers and refrigerate for up to 1 day.

From Real Simple.com