1. Preheat the oven to 350°. Put the beets in a baking dish, cover with foil and bake for about 1 hour, or until tender. When cool enough to handle, peel the beets and cut into wedges.
2. In a small saucepan, boil the orange juice until reduced by half, about 8 minutes. Add the sugar and simmer for 2 minutes. Remove from the heat and let cool slightly. Whisk in the wasabi powder, cover and let stand for 5 minutes.
3. In a blender, combine the beets and orange juice mixture and blend until smooth. Transfer the sauce to a bowl, stir in the zest and season with salt. Transfer to jars and refrigerate.
Make Ahead: The sauce can be refrigerated for 1 month.