Peel and dice eggplants. Sauté in hot oil in a Dutch oven over medium-high heat 5 minutes; remove eggplant from pan, and set aside.
Add onion to pan; sauté 5 minutes or until tender. Add tomato sauce and celery; sauté 5 minutes or until celery is tender.
Return eggplant to pan; stir in capers and next 6 ingredients. Reduce heat, and simmer, stirring often, 20 minutes. Let cool 1 hour. Garnish, if desired. Serve with rustic bread slices.
Note: Caponata may be stored in refrigerator up to 1 week.