Bring a large pot of salted water to a boil, then add the pasta. Cook until al dente according to package instructions, usually about 8 minutes, until the pasta is firm but tender. Drain and rinse thoroughly with cold water to stop the cooking and cool it down quickly.
Transfer the drained pasta to a large mixing bowl. While still slightly warm, add the basil pesto and toss gently with a spoon or spatula until the noodles are evenly coated. The warmth helps the pesto oils loosen and spread evenly over each strand.
While the pasta cools slightly, chop the cherry tomatoes in half, slice the cucumbers into thin rounds, and dice the bell peppers into small pieces. Add all the chopped vegetables to the bowl with pasta.
Drizzle the olive oil over the pasta salad and gently fold everything together to distribute the oil and combine flavors. The salad will start to look shiny and vibrant with all the ingredients evenly mixed.
Sprinkle the Parmesan cheese over the top and give the salad a final gentle toss. Cover the bowl with plastic wrap and refrigerate for at least 1 hour to let flavors meld and the salad to chill thoroughly.
Remove from the refrigerator, give it a quick toss, and serve cold. The pasta should be firm and slightly sticky, coated in bright green pesto with crisp vegetables for a satisfying bite. Enjoy immediately for the best texture and flavor!
