Preheat oven to 400 degrees.Combine both flours, sugar, baking powder, baking soda and salt in a large bowl; make a well in center of mixture. Combine coconut milk, oil and egg in a bowl; add to flour mixture. Stir just until moist. Gently fold in pineapple and coconut flakes. Spoon batter into 12 muffin cups lined with paper wrappers.Bake at 400° for 18 minutes or until lightly browned. Remove muffins from pan; cool on a wire rack. After the muffins have cooled, combine powdered sugar and coconut milk in a bowl. Drizzle the glaze over the muffins. Garnish with pineapple slices and coconut shavings if desired.