For each spider, cut 4 pieces of licorice measuring 2 to 3 inches in length. Using a knife, cut each licorice piece in half lengthwise. Place each pair of legs opposite each other, flat-side down, on lightly greased wax paper. Cover inside ends of licorice with icing. Gently press cookie onto icing and legs. Use icing to "glue" the candies onto cookie for eyes. Allow icing to set up; carefully transfer cookie spiders to serving plates.