Rinse the fresh cranberries under cold water, removing any that are bruised or damaged.
In a medium saucepan, combine the water, granulated sugar, and salt. Heat over medium-high heat until the mixture comes to a boil, stirring occasionally.
Once the sugar has dissolved, add the cranberries to the saucepan. Bring back to a boil, then reduce the heat to medium-low.
Stir in the orange zest, orange juice, and ground cinnamon (if using). Allow the mixture to simmer for about 10-15 minutes, or until the cranberries have burst and the sauce thickens.
Remove the saucepan from heat. If you prefer a smoother sauce, you can blend it with a food processor or use an immersion blender until the desired consistency is reached.
Allow the cranberry sauce to cool completely at room temperature before transferring it to a serving dish or airtight container. The sauce will thicken further as it cools.
Serve the cranberry sauce chilled or at room temperature. It pairs wonderfully with roasted meats and can be stored in the refrigerator for up to one week.