Working in 2 batches, blend first 5 ingredients in processor until smooth; add ginger and cherries and process until finely chopped and well incorporated. Using on/off turns, mix in chocolate just until blended (do not puree). Transfer filling to large bowl. (Filling can be prepared 1 day ahead. Cover and refrigerate.Bring to room temperature before continuing.)
Working in batches, transfer filling to pastry bag without tip. Pipe into shells. Sprinkle ends with pistachios. Chill at least 2 hours and up to 6 hours. Sift powdered sugar over cannoli and serve.
*Italian cream cheese; available at many supermarkets and Italian markets.