In a medium bowl, combine the fresh orange juice, orange zest, granulated sugar, and salt. Stir until the sugar and salt are dissolved.
Add the fresh cranberries to the bowl and stir to coat them evenly with the orange juice mixture.
Cover the bowl and refrigerate for at least 30 minutes to allow the flavors to meld and the cranberries to soften slightly. For a smoother relish, you can pulse it a few times in a food processor before serving.
Serve chilled as a condiment or side dish.
Notes
This relish can be made a day in advance and stored in the refrigerator.