Preheat oven to 400°F.
Line a roasting pan with aluminum foil.
Place the beets in the pan.
Rub the beets with olive oil and sprinkle with salt.
Cover the beets with another sheet of aluminum foil.
Roast for 1 to 2 hours, depending on the size of the beets.
After 1 hour, test every fifteen minutes by poking a beet with a fork. Once the fork tines go in easily, the beets are tender and cooked. Remove from the oven.
While the beets are cooling, prepare the balsamic glaze.
In a small sauté pan, add the balsamic vinegar and sugar.
Heat on high until the vinegar has reduced to a syrup consistency.
Remove from heat.
After the beets have cooled for several minutes, but are still warm to the touch, peel off the outer skins and discard.
Cut the beets into quarters or more, bite-sized pieces.
Place beets in a serving bowl.
Pour balsamic glaze over the beets.
Stir in grated orange zest, and add salt and pepper to taste.
Garnish with a little orange zest to serve.