1. From oranges, grate 1/2 tsp peel and squeeze juice. Add enough water to juice to equal 1 cup.
2. In 2-quart saucepan, heat cranberries, sugar, cinnamon, orange peel, and orange juice to boiling, over high heat, stirring occasionally. Reduce heat to medium and cook, uncovered, 5 to 8 minutes or until most of the cranberries pop, stirring occasionally. Mixture thickens as it chills.
If you prefer less "whole" pieces of cranberry, strain part of the mixture through a strainer.
Spoon sauce into bowl; cover and refrigerate until well chilled, about 3 hours or up to 4 days. Garnish with orange peel slivers.