1In large bowl, stir together cookie mix and lime peel until blended. Add butter, egg and lime juice. Beat with electric mixer on medium-low speed until blended and soft dough forms.
2On 17-inch piece plastic wrap, shape dough into 12-inch log. Wrap tightly; freeze at least 30 minutes or until firm enough to slice.
3Heat oven to 375°F. Unwrap dough; cut into 1/4-inch slices. Onto ungreased cookie sheets, place slices 2 inches apart, reshaping if necessary; lightly sprinkle with salt.
4Bake 8 to 10 minutes or until pale brown on bottom. Cool 1 minute; remove from cookie sheets to cooling racks. Cool completely before storing in airtight container. If desired, garnish cookies with freshly grated lime peel just before serving.