In a large bowl, cream butter and granulated sugar until light and fluffy. Beat in egg, zucchini and lemon zest. Combine the flour, baking soda, baking powder, cinnamon and salt; gradually add to the creamed mixture and mix well. Stir in raisins and walnuts.
Drop by tablespoonfuls 3 in. apart onto lightly greased baking sheets. Bake at 375° for 8-10 minutes or until lightly browned. Remove to wire racks to cool.
For glaze, combine confectioners' sugar and enough lemon juice to reach a thin spreading consistency. Spread or drizzle over cooled cookies.