Preheat oven to 350°F. Place 1/2 cup of the pistachio nuts in bowl of food processor; cover. Pulse until finely chopped. Mix flour and sugar in medium bowl. Cut in butter with pastry blender or 2 knives until mixture resembles coarse crumbs. Add pistachio nuts; toss to mix well. Add water; stir until a soft dough forms. Press dough onto bottom and up sides of 10-inch tart pan with removable bottom. Bake 10 to 15 minutes or until lightly browned. Cool completely on wire rack. Remove sides of pan
Place cream and chocolate in medium microwavable bowl. Microwave on HIGH 1 minute, stirring halfway through cooking time. (Chocolate will not be completely melted.) Stir until chocolate is completely melted. Cool just until mixture starts to thicken. Spread evenly in bottom of tart shell. Cool completely
Place crystallized ginger in bowl of food processor; cover. Pulse until just coarsely chopped. Add remaining 1/4 cup pistachio nuts; cover. Pulse until chopped. Sprinkle over chocolate in tart shell
Refrigerate until ready to serve. Let stand 5 to 10 minutes before serving.