Sort through the cranberries and pick out any that are soft or mushy
Cut off the tops and remove the seeds and ribs of the jalapeños. Finely mince the flesh into even, small pieces. Chop up as much or as little of the seeds and ribs as you would like for extra kick. For a very mild relish with little to no heat, leave the seeds out.
In a food processor or high powered blender, pulse the cranberries in short bursts. You want them finely chopped but not mushy.
Add the pulsed cranberries to a large bowl. Add in the sugar, salt, mustard seed, coriander, and ginger. Stir to combine and fully incorporate with the chopped cranberries.
Add in the onion, jalapeño, and orange zest. Stir to combine.
Pour in the vinegar and orange juice. Stir to combine.
Cover and allow to rest in the fridge (or transfer to a jar with a tight lid) for at least 24 hours.
Once flavors have come together, taste and adjust salt and sugar as needed.