In a medium sized bowl, rinse the cranberries with cool water, and remove any stems or blemished berries. Drain the cranberries in a colander.

Heat orange juice and sugar to boiling in 3-quart saucepan over medium heat, stirring occasionally until the sugar dissolves.

Stir in cranberries. Heat to boiling over medium heat, stirring occasionally. Continue boiling about 5 minutes longer, stirring occasionally, until cranberries begin to pop. Simmer for about 20 minutes. Don't worry if every single cranberry does not completely pop. Pour sauce into bowl or container. Before serving, add on the orange zest and orange slices. Refrigerate about 3 hours or until chilled.