1. Preheat oven to 350ºF. Line an 8-inch-square pan with foil so that foil overhangs sides. Mist with cooking spray.
2. Make crust: Process cookies in food processor until ground. Pulse in butter. Press evenly into pan. Bake until firm, 10 to 12 minutes. Cool slightly.
3. Make filling: With an electric mixer on medium speed, beat cream cheese and sugar until smooth, about 2 minutes. Beat in pumpkin, then eggs, 1 at a time. Beat in vanilla, flour, spice and salt until just combined.
4. Pour mixture into pan. Put pan on a large rimmed baking sheet; place in oven. Pour hot water into baking sheet until it's nearly filled. Bake until cheesecake is set around edges but jiggles slightly in center, 40 to 45 minutes. Remove pan from sheet; cool completely on rack. Cover with plastic wrap. Chill until firm, at least 3 hours.
Note: Pipe whipped cream onto bars in a circular motion. Use mini chocolate chips for eyes.