Preheat oven to 350ºF. Grease or line a baking sheet with parchment paper. With an electric mixer, blend together pumpkin, sugar, oil, egg, and vanilla until well combined and smooth. Add in flour, baking powder, baking soda, cinnamon, and salt. Mix until well blended. Add chocolate chips and mix to combine. Drop mixture onto baking sheet a heaping teaspoonful at a time. For larger cookies, drop more dough. Bake for 10-12 minutes. Make glaze by mixing water and powdered sugar together until smooth. Once cookies are out of the oven, while cookies are still warm, brush glaze over top. Store in airtight container.