Combine flour and salt in a bowl and set aside. In a food processor, combine confectioners’ sugar, chopped walnuts or pecans, and flaked coconut.
Process until the walnuts or pecans are finely ground, 15-20 seconds.
In a separate bowl, add butter and beat until creamy with a mixer, approximately 1 minute. Add the ground walnut mixture and beat until well blended, approximately 1 minute.
Add in coconut extract and flour mixture, beating just until combined.
The resulting dough should be crumbly in appearance, like pebbles.
Pour the dough onto a large piece of plastic wrap and form into a ball, making sure it’s covered on all sides. Chill until firm, around 2-3 hours.
Let chilled dough sit at room temperature until it softens up (45 minutes). Preheat the oven to 350°F. Using a cookie scoop, scoop the dough into even sizes.
Lightly spray a baking sheet with cooking spray. Arrange the balls 1-1 ½ inches apart on baking sheets. Bake until the edges of the cookies barely begin to brown, 12 to 14 minutes.
Let the cookies cool for 5-7 minutes. Make coating by processing flaked coconut and confectioners' sugar. Roll each cookie in powdered mixture.
Repeat until all the cookies are coated.