Bring a large pot of water to a boil, and add pasta. Cook pasta according to package directions. Drain and run under cold water to cool; set aside. While pasta is cooking, prep vegetables. Toss onion, cucumber, tomatoes, olives and feta together in a very large bowl. Add cooked pasta, toss together and set aside. In a small bowl, whisk together all of the vinaigrette ingredients. Pour over pasta mixture, and toss well to coat. Cover and refrigerate salad for at least 2 hours before serving. In another bowl, or a mason jar, combine all of the vinaigrette ingredients again. Whisk to combine well, or put lid on jar and shake to combine. Cover and place in the refrigerator until ready to serve the salad. Just before serving, shake or whisk reserved dressing, and pour over pasta salad. Toss to coat, and serve.