Into a kettle of salted boiling water stir wheat berries and cook at a slow boil 30 minutes. Stir in barley and cook grains at a slow boil 40 minutes. While grains are cooking, in a large bowl stir together onion, garlic paste, vinegar, and oil. Drain grains well and add to onion mixture. Toss mixture well and cool. Add scallions, corn, mozzarella, tomatoes, chives, and salt and pepper to taste and toss well. Salad may be made 1 day ahead and chilled, covered. Bring salad to room temperature before serving. Serve salad with parsley salad. Serves 6 as a main course or 8 to 10 as a side dish. Gourmet July 1994