Cook the pasta according to the directions on the package, adding the cut green beans for the last 5 minutes of cooking.
In a large bowl, blend together the balsamic vinegar, olive oil, salt and pepper to taste.
Stir in the tomatoes, garlic, basil and chives.
Drain the pasta, rinse under cool water, drain well and add to the tomatoes mixture; season with salt and pepper to taste.
Crumble the Feta cheese over the pasta and serve.