In a medium saucepan, add mustard seeds, white wine, sugar, white wine vinegar, mustard powder and a small pinch of salt, whisking to combine. Bring the mixture to a boil over medium-high heat, then add the cranberries. Once the mixture comes back up to a boil, drop the heat to medium-low, and simmer until the cranberries have softened and the mixture thickens a bit (about 20 minutes). Take the mixture off the heat, stir in the orange zest, and carefully fish out the spices*. Let cool completely, then season to taste with additional kosher salt.