Combine dates, water, and maple syrup in a heavy saucepan over medium heat. Bring to a boil; cook 12 minutes or until most liquid is absorbed, stirring frequently. (Mixture will look like jam.) Stir in rind; cool completely.
Preheat oven to 400°.
Beat sugar and butter with a mixer at medium speed until smooth. Lightly spoon flour into a dry measuring cup; level with a knife. Combine flour, oats, baking soda, and salt. Stir flour mixture into sugar mixture (mixture will be crumbly). Press 2 cups flour mixture into bottom of a 13 x 9-inch baking pan coated with cooking spray. Spread date mixture over flour mixture. Sprinkle with remaining flour mixture. Bake at 400° for 20 minutes or until golden brown. Cool completely in pan on a wire rack.