Spray 24 mini muffin cups or 8 regular sized cups with cooking spray. Combine muffin mix and lemon rind. Stir in water until just blended but still slightly lumpy. Quickly stir in blueberries. Fill cups 2/3 full. Sprinkle with sugar. Bake in preheated 400 degree oven for 10-12 minutes for mini muffins, or 15-20 for regular size muffins. Let stand a few minutes before removing from pan.