Add rolled oats to food processor and process into a coarse flour.
In a large mixing bowl, combine oat flour, cacao, baking power and salt.
Zest orange, add zest to food processor. Peel orange, remove seeds and add orange flesh to food processor. Add water, pitted dates and banana, process until smooth. Add to dry ingredients and stir to combine.
Using a cookie scoop (or your hands), form cookies and place on parchment-lined baking sheet. Bake for 12 minutes.
Glaze
Zest orange to obtain 1 tsp zest. Peel orange, remove seeds and add flesh to food process along with zest and all remaining glaze ingredients. Process until smooth, stopping to scrape down sides as needed.
Immediately after removing cookies from oven, carefully use your thumb to make 1/4 inch deep "prints" in the middle of all cookies.
Using a small spoon, add approximately 1 tsp of glaze to each cookie. Enjoy warm or cold.