In a medium saucepan, bring blueberries, the 1/2 cup sugar, the 1 teaspoon of orange peel, orange juice, and salt to boiling over medium heat, mashing berries and stirring with a fork; reduce heat. Simmer, uncovered, for 5 minutes, stirring frequently. Remove from heat; cool slightly. Remove 1 cup of the mixture; set aside. Transfer the remaining blueberry mixture to a food processor or blender. Cover; process or blend till almost smooth. Pour blueberry mixture through a fine mesh sieve into a medium bowl, pressing on solids with back of a spoon; discard solids. Add the reserved 1 cup of blueberry mixture and the 1 cup of whipping cream to sieved mixture. Cover; chill blueberry mixture in the refrigerator at least 4 hours or up to 24 hours.