Preheat oven to 350°.
Toss beets, salt and oil together in medium mixing bowl. Put beets in a high-sided roasting pan and add enough water to cover beets halfway.
Cover roasting pan with aluminum foil. Bake beets until fork tender. Smaller beets will take about 30 to 45 minutes; larger beets, about 60 minutes. Allow to cool 5 to 10 minutes.
Use a clean kitchen towel, or your hands, to rub the skin off the beets. Cut each beet into 4 wedges. Refrigerate until thoroughly chilled, about 30 minutes.
While the beets are chilling, cut rind from the oranges to expose the flesh. Using a sharp paring knife, remove the fruit from between the segments (called supremes). (Do this over a bowl to collect the juice for another use.)
In a medium bowl, add chilled beet wedges, oranges, green onion, tarragon, rice wine vinegar, orange blossom water and sugar. Toss to coat and season with salt and pepper to taste. Spoon onto salad plates and garnish with walnuts.
Recipe courtesy of Chef Gabe Garcia, Tierra Sur at Herzog Wine Cellars