Heat oven to 375 degrees. In medium bowl, beat butter, 1/2 cup powdered sugar and lime juice with electric mixer on medium speed until smooth. Beat in flour, salt, pecans and 2 t. lime peel.
Shape dough into 1-inch balls. Place 1-inch apart on ungreased cookie sheets. Bake 8-10 minutes, or until cookies begin to brown. Meanwhile in a small bowl. Stir 1 cup powdered sugar and 1 t. lime peel with fork. Roll warm cookies into sugar mixture. Place on wire rack. Roll in sugar again. Makes about 4 dozen.