Bring a large pot of water to a boil and cook pasta one minute less than package directions. Drain pasta, and toss with olive oil. Place pasta flat on a sheet pan to cool.
Cut the feta in pieces about the same size as the tomatoes. Tip: wet the knife at each cut to avoid crumbling the feta.
Add pasta, tomatoes, olives and feta to a large mixing bowl.
Add pesto; toss to combine and serve.
Optional: If you want a stronger flavor, add half of a red onion thinly sliced.
