Put the cranberries in a saucepan. Remove wide strips of zest from 1/2 orange with a peeler; add to the saucepan with the juice of both oranges (about 1/2 cup). Add the sugar, coriander, a pinch of salt and 1 cup water. Bring to a simmer over medium heat; cook, stirring occasionally, until the berries burst and the sauce thickens, 15 to 20 minutes.
Remove from the heat and remove the orange zest; stir in the vanilla. Transfer to a blender and puree until smooth. Strain through a fine-mesh sieve into a serving dish, pushing the sauce through with a rubber spatula. Refrigerate until set, at least 3 hours.