1. With sharp knife, cut veal breast into individual ribs. On waxed paper, coat veal ribs with flour. Reserve leftover flour on waxed paper. In 8-quart Dutch oven over medium heat, in hot olive or salad oil, cook ribs, half at a time, until well browned on all sides, removing pieces to a plate as they brown.
2. In drippings remaining in Dutch oven, over medium heat, cook onion and garlic until tender. Stir in reserved flour until blended. Add tomatoes with their liquid, stirring to break up tomatoes into small pieces. Return veal ribs to Dutch oven; stir in water, salt, and sugar; over high heat, heat to boiling. Reduce heat to low; cover and simmer 1 1/2 hours, stirring often.
3. Add potatoes and cook 15 minutes. Add zucchini and cook 10 minutes longer, stirring occasionally, until veal ribs and vegetables are fork-tender. Skim fat from sauce.