Bring a large pot of salted water to a boil. Add the rigatoni and cook until al dente, about 8-10 minutes, until it just bites firm with a slight chew.
Drain the pasta in a colander and rinse quickly under cold water to stop the cooking process and cool it down. Shake off excess water and set aside in a large mixing bowl.
Add the basil pesto to the cooled pasta, using a spatula or spoon to coat each strand evenly with the vibrant green sauce. The oily pesto should cling nicely to the noodles, giving them a glossy appearance.
Halve the cherry tomatoes and gently fold them into the pasta mixture. The juicy, colorful tomatoes add a fresh burst of sweetness and contrast to the pesto.
Grate the Parmesan cheese over the pasta and toss again to distribute evenly, creating a salty, nutty flavor throughout the dish.
Squeeze fresh lemon juice over the salad, then drizzle with a tablespoon of extra virgin olive oil. Gently toss everything together to brighten the flavors and add a glossy sheen.
Season with salt and freshly ground black pepper to taste. Taste and adjust seasoning as needed, adding more lemon or salt for balance.
Cover the bowl and refrigerate the pasta salad for at least 30 minutes to allow flavors to meld and the dish to chill thoroughly.
Once chilled, give the salad a gentle stir to redistribute the pesto and ingredients. Serve cold, garnished with additional Parmesan if desired.
