In a medium saucepan, combine water, orange juice, granulated sugar, and orange zest (if using). Bring to a boil over high heat.

Reduce heat to medium. Add the cranberries and ground cinnamon. Simmer until two-thirds of the cranberries have burst and the mixture has slightly thickened, about 10-12 minutes.

Taste the sauce and season with fine sea salt. Add more sugar if you prefer it sweeter.

Let it cool completely before serving or storing in an airtight container in the refrigerator for up to 1 week.