Bring a large pot of salted water to a boil. Cook the pasta according to the package directions until al dente. Drain and run under cold water to cool the pasta.
Add the tomatoes, cucumbers, onion, and olives to a large mixing bowl. Add the pasta to the same bowl.
In a small mixing bowl, whisk the salt, pepper, and sugar into the Greek salad dressing.
Pour the dressing over the pasta salad ingredients, sprinkle with feta cheese, and gently toss together until coated.
Cover the bowl with plastic wrap and chill in the fridge until ready to serve, preferably at least 1 hour. Before serving, stir the pasta salad once more. If needed, you can add a little extra dressing, too.