In large bowl, combine 1/2 cup sugar, brown sugar, cocoa, shortening and margarine; beat until light and fluffy. Add orange peel, vanilla and egg; blend well. Add flour, baking soda and salt. Cover with plastic wrap; refrigerate 1 hour for easier handling.
Heat oven to 375°F. Shape dough into 1-inch balls; roll in sugar. Place 2 inches apart on ungreased cookie sheets.
Bake at 375°F. for 10 to 12 minutes or until set. Immediately top each cookie with a candy kiss, pressing down firmly so cookie cracks around edges. Remove from cookie sheets.