Preheat oven to 350°. Line a 13x9-inch baking pan with foil, letting excess extend over sides of pan; spray foil with cooking spray.
In a large bowl, whisk together sugar, flour, and salt. Add butter, eggs, 1 teaspoon orange zest, and extract, and beat with a mixer at medium speed until well combined. Spread batter into prepared pan.
Bake for 30 minutes or until golden brown and center is set. Remove from oven, and prick all over with a fork. In a small bowl, whisk together confectioners’ sugar, orange juice, and remaining 1 teaspoon zest until smooth. Pour onto warm bar in pan, and let cool completely.
Using excess foil as handles, remove from pan, and cut into bars. Garnish with zest strips, if desired. Store in an airtight container for up to 2 days.