Bring a large pot of salted water to a boil. Cook the pasta according to the package directions. Drain, rinse with cold water, drain again, and toss with 1 tablespoon olive oil. Let cool.

In a small jar, combine 6 tablespoons olive oil, the lemon juice, garlic, oregano, ½ teaspoon salt, and ½ teaspoon pepper. Shake well to combine.

In a large bowl, combine the pasta, tomatoes, feta, and dressing. Toss to combine. Can be made ahead to this point and stored in the refrigerator, covered, until serving time. Before serving, stir in the arugula and taste. Add more salt and pepper, if desired.