Bring a large pot of salted water to a boil. Add the pasta and cook until al dente, following package instructions. Drain, rinse under cold water until cool, and shake dry.

Combine the halved cherry tomatoes and a pinch of salt in a large bowl. Stir and set aside.

To make the pesto, place the pistachios, capers, and garlic in a food processor. Pulse until coarsely chopped. Add the basil, salt, and pepper, then pulse until finely chopped. Add lemon juice, then gradually drizzle in olive oil while pulsing until smooth. Scrape the pesto into the bowl with the tomatoes.

Add the cooled pasta to the bowl and toss to coat evenly. Let sit for 5 minutes to absorb flavors.

Mix in the arugula and a few torn basil leaves just before serving. Adjust seasoning with additional salt, lemon juice, or olive oil as needed.