In a large bowl, combine flour, oat bran, sugar, baking powder, baking soda and salt. In a separate bowl, beat buttermilk, oil, egg and citrus rinds. Add to dry ingredients, mixing until just dampened and still lumpy. Lightly stir in dates and spoon into lightly greased muffin cups. Sprinkle with sesame seeds. Bake at 375 F for 20 minutes.