Preheat oven to 350°. In a bowl, cream butter and sugar until light and fluffy. Gradually beat in egg, orange juice and zest. In another bowl, whisk flour, baking powder and salt; gradually add to creamed mixture, mixing well.
Using a cookie press fitted with a bar disk, press long strips of dough onto ungreased baking sheets; cut ends to release from disk. Cut each strip into 3-in. lengths (no need to separate them).
Bake 8-10 minutes or until set (do not brown). Re-cut cookies if necessary. Remove from pans to wire racks to cool completely.
Place walnuts in a shallow bowl. In a microwave, melt chocolate chips and shortening; stir until smooth. Dip each cookie halfway in chocolate; allow excess to drip off. Sprinkle with walnuts. Place on waxed paper; let stand until set.