Bring a large pot of salted water to a rolling boil. Add the capellini pasta and cook for about 5 minutes, or until tender yet al dente. Drain and rinse under cool running water to halt cooking.

In a large mixing bowl, whisk together the fresh lemon juice, olive oil, garlic salt, and black pepper to create the dressing.

Once the pasta is cooled, add it to the bowl with the dressing. Gently fold in the diced tomatoes and capers.

Add the chopped parsley and lemon zest to the mixture and toss lightly to combine.

Serve immediately or chill in the refrigerator for about 30 minutes before serving.