Prepare barbecue or preheat broiler. Whisk vinegar, lemon juice, lemon peel and oregano in medium bowl. Gradually whisk in oil. Season to taste with salt and pepper. Brush onions on both sides with some of dressing. Season onions with salt and pepper. Grill onions until lightly charred and tender, turning occasionally, about 12 minutes. Transfer to plate and cool. Toss greens with remaining dressing. Transfer to serving bowl. Arrange onions on top. Sprinkle with goat cheese and mint and serve.
c.1997, M.S. Milliken & S. Feniger, all rights reserved