Place wafer cookies in a food processor and pulse on and off until finely crushed. Drizzle with melted butter and vanilla and process until crumbs begin to stick together. Pour into a 15 x 10 x 1-inch jellyroll pan and press evenly into bottom. Refrigerate while making bar batter.
In a medium bowl, whisk flour, baking soda and salt. In a large bowl, with an electric mixer, beat softened butter and cream of coconut until smooth. Beat in eggs on medium speed. On low, beat in flour mixture. Fold in 1 1/2 cups of the chocolate chips, 1 cup of the coconut and the walnuts. Pour over crust in pan, spreading to edges. Bake at 350°for 35 minutes, until puffed, golden and set. Cool in pan on a wire rack.
Chop remaining 3/4 cup coconut and bake at 350° for 10 minutes, until golden.
Place remaining 1/2 cup chocolate chips in a glass bowl. Microwave 45 seconds and stir. Microwave an additional 45 seconds and stir until smooth. Transfer to a piping bag or small resealable plastic bag. Snip off a small corner and drizzle over cooled cake. Sprinkle with toasted coconut. Let set, then cut into 24 bars.