Preheat oven to 350 degrees. Dissolve the coffee in water in a medium bowl. Stir in the margarine and powdered sugar. Stir in the flour and 1/2 cup pistachios, using your hands if necessary, until a stiff dough forms. Divide the dough in half. Shape each half into a ball. Pat each ball into a 6-inch round, about 1/2-inch thick, on a lightly floured surface. Cut each round into 16 wedges. Arrange the wedges on an ungreased cookie sheet about 1/2 inch apart with the pointed ends toward the center. Bake for about 15 minutes, or until golden brown. Immediately remove from the cookie sheet. Cool completely on wire racks. Place the remaining 1/2 cup pistachios in a small dish. Place the chocolate and shortening in a small microwavable bowl. Microwave uncovered on medium power for 3 to 4 minutes, stirring after 2 minutes, until the mixture can be stirred smooth and is drizzling consistency. Dip one edge of each cookie into the chocolate, then into the nuts. Place on waxed paper until the chocolate is firm. Nutrition Analysis: 100 calories, 1g protein, 10g carbohydrate, 6g fat, 0mg cholesterol, 55mg sodium.