Steam potatoes, covered, 15 minutes or until tender. Let cool. Cut each potato into 4 wedges, and cut each wedge in half crosswise.
Combine potatoes and next 5 ingredients (potatoes through zucchini) in a large glass dish; set aside. Combine vinegar and next 9 ingredients (vinegar through red pepper) in a jar; cover tightly, and shake vigorously. Pour over vegetables, and toss gently to coat. Cover and marinate in refrigerator 8 hours, stirring occasionally.