Rinse cranberries and discard any soft berries.Combine cranberries, sugar, liquid, zest, and salt in a saucepan.Heat over medium until sugar dissolves and berries begin to soften.Simmer until most cranberries burst, about 10 to 12 minutes.Stir in vanilla extract and taste for sweetness.Cool in the pot for 20 to 30 minutes.Transfer to a container and chill at least 1 hour before serving.