Place cashews in a food processor; cover and process until finely chopped.
In a large bowl, cream butter and sugars until light and fluffy. Beat in 1 teaspoon vanilla. Combine the flour, salt and chopped cashews; gradually add to creamed mixture and mix well.
Divide dough in half; shape each into a ball, then flatten into a disk. Wrap in plastic wrap and refrigerate for 30 minutes.
On a lightly floured surface, roll one portion of dough to 1/4-in. thickness. Using a floured scalloped round 3-in. cookie cutter, cut a semicircle from one corner of the dough, forming the inside of a crescent shape. Reposition cutter 1-1/4 in. from inside of crescent; cut cookie, forming a crescent 1-1/4 in. wide at its widest point. Repeat with remaining dough. Chill and reroll scraps if desired.
Place 1 in. apart on ungreased baking sheets. Bake at 375° for 6-7 minutes or until edges begin to brown. Cool for 2 minutes before removing from pans to wire racks to cool completely.
Combine the confectioners' sugar, milk and remaining vanilla; spread or drizzle over cookies as desired. Sprinkle with chopped cashews if desired. Leave some cookies plain or sprinkle them with additional confectioners' sugar if desired. Let iced cookies stand until set. Store in an airtight container. Yield: 6 dozen.