Preheat oven to 325 degrees F. Cream butter in a bowl. Gradually add confectioners sugar and salt. Beat until light and fluffy. Add almonds and vanilla. Blend in flour gradually and mix well. Shape into crescents using about 1 teaspoon for each cookie. Place on ungreased cookie sheets, and bake for 15 to 20 minutes. Do not brown. Cool slightly, then roll in the extra confectioners' sugar.