Preheat oven to 350°. In a food processor, pulse together flour, sugar, cornstarch, orange zest, and salt. Add butter, then pulse until fine and crumbly. Remove bowl from food processor and stir in dried blueberries.
Measure 2 tbsp. mixture into each of 36 mini muffin cups*, pressing down firmly.
Bake until golden brown, about 15 minutes. Let cool at least a few minutes before serving.
*If you don't have mini muffin pans, press 1/4 cup mixture into each of 18 regular muffin cups and bake about 20 minutes.
Note: Nutritional analysis is per shortbread.