Sift flour with salt and baking soda. In small bowl with mixer at medium speed, cream butter and sugar; add egg and lemon rind. Beat well. At low speed mix in flour slowly, then add lemon juice.
Refrigeate for 1/2 hour. Meanwhile, heat oven to 375 F degrees. Greased 2 cookies sheets and shape cookie dough by tablespoonfuls into balls. Roll in granulated sugar until coated. Place 2 inches apart on cookie sheets. Using a fork, press down each ball until it is flat and round.
Bake 10-12 minutes or until light golden brown. Remove to rack, cool. Makes about 25 cookies.