For dressing: Place all ingredients in a jar. Close lid tightly and shake until blended.
In a large pot of lightly salted water, cook pasta according to package directions. While pasta is cooking, soak red onion in ice water to mellow its flavor. Drain cooked pasta and place in a large bowl. Drain onions and pat dry, add to pasta, Add dressing, olives, peppers and feta to warm pasta and toss. Serve at room temperature.