Preheat the oven to 400℉. Spray 16 muffin cups with nonstick spray.
Place oats in food processor; pulse until oats resemble coarse-meal. Place in a large bowl. Add flours, brown sugar, cinnamon, baking powder, baking soda and salt. Whisk together.
In a separate bowl, stir together buttermilk, oil, lemon rind, and eggs. Add to flour mixture; stir just until dry ingredients are incorporated and moist.
In a medium bowl, toss blueberries with 2 tablespoons flour. Gently fold floured blueberries into the batter.
Spoon batter into the muffin cups, dividing it evenly between 16. Sprinkle with sugar.
Bake for 18 to 22 minutes, or until toothpick inserted into a muffin comes out clean.