1. Prepare pasta according to package directions, adding 1/2 tsp. salt to water; drain well.
2. Place pasta in a large bowl, and stir in tomatoes, olives, and onion.
3. Whisk together olive oil, next 3 ingredients, and remaining 1/4 tsp. salt; add to pasta mixture, tossing to coat. Let stand 10 minutes; stir in feta. Garnish, if desired.
Kitchen Express: Substitute 6 Tbsp. balsamic vinaigrette for olive oil, vinegar, garlic, and oregano. Proceed as directed.