Whisk all ingredients in small bowl. Season with salt and pepper. for salad: Preheat oven to 400°F. Toss beets with 1 tablespoon oil in 11x7-inch metal baking pan. Roast beets until tender, about 1 hour 10 minutes. Cool beets; peel and cut into 1/2-inch wedges. (Dressing and beets can be made 1 day ahead. Cover separately; chill. Bring both to room temperature before continuing.)
Mix lettuces, walnuts and dressing in large bowl; toss. Divide among plates. Arrange beets around greens; sprinkle with goat cheese and orange peel.