Add 1/4 cup toasted pine nuts, 1 clove garlic, and 2 tablespoons lemon juice to a food processor and pulse until finely chopped.
Add 2 cups packed basil leaves and 1/3 cup grated Parmesan to the processor and pulse until the basil is finely chopped.
With the processor running on low, slowly drizzle in 1/3 cup extra virgin olive oil until the pesto is smooth, scraping the bowl as needed; set aside.
Cook 20 ounces cheese tortellini in a large pot of boiling salted water according to package directions until al dente, then drain and rinse under cold water until no longer warm.
Transfer the cooled tortellini to a large mixing bowl and add the prepared pesto; toss gently to coat evenly.
Add 1 1/2 cups fresh arugula, 1 cup halved cherry tomatoes, 1 cup small mozzarella balls, and the remaining 1/4 cup toasted pine nuts; toss to combine and season with salt and pepper to taste.
Garnish with fresh basil and serve immediately or chill as desired.