Fill a 4-quart kettle 3/4 full with salted water and bring to a boil for beans and orzo.
Chop onion and mince garlic. Quarter and seed tomatoes. Cut quarters lengthwise into 1/4-inch thick slices. Trim beans and cut into 1-inch pieces. In a large skillet cook onion and garlic in oil over moderate heat until onion is softened. Add tomatoes and cook, stirring, until tomatoes are softened, about 2 minutes. Remove skillet from heat.
Have ready a bowl of ice and cold water. In boiling salted water blanch beans 1 minute. With a slotted spoon transfer beans to ice water to stop cooking. Drain beans well in a colander and pat dry. Add beans to tomato mixture and return water in kettle to a boil. Boil orzo until al dente and drain in colander. Add orzo to bean mixture with vinegar, parsley, feta, and salt and pepper to taste, tossing to combine well.
Recipe courtesy of Gourmet Magazine