Bring a large pot of salted water to a boil and cook the capellini (angel hair) according to package directions until al dente, about a few minutes; drain and rinse under cool water to stop cooking.
In a large bowl, whisk together the juice of 2 medium lemons, 1 teaspoon lemon zest, 3 tablespoons olive oil, 1 1/2 teaspoons garlic salt, and 1/2 teaspoon black pepper until combined.
Add the cooled pasta to the dressing, then fold in the diced tomatoes (with seeds removed) and drained capers until evenly coated.
Stir in the finely chopped curly leaf parsley, toss once more, and serve immediately or chill until ready to serve.
