If you want to quickly rehydrate dried cranberries or Raisins, put them in a small bowl with a little water or juice (I like orange with dried cranberries). Cover with plastic wrap, microwave 1 minute, then let sit for about 5 or so to soak up the liquid. Use any leftover liquid as part of the liquid the recipe calls for.
When using dried cranberries in place of fresh or frozen, remember that the dried ones are sweetened. That may or may not make a difference in the finished product.