Cook the rotini or penne pasta according to package directions. Drain and let cool.
In a large mixing bowl, combine the cooled pasta with the halved cherry tomatoes, diced cucumber, diced red bell pepper, and thinly sliced red onion.
Pour the pesto sauce over the pasta mixture and toss to coat evenly.
Top with shredded Parmesan cheese and toss gently.
Refrigerate for at least 30 minutes to let the flavors meld before serving.
Notes
This pesto pasta salad can be served with grilled chicken or tofu for added protein. It also works well with a squeeze of fresh lemon juice for a citrusy kick.