In a food processor or zipped top bag (using a rolling pin), crush graham crackers until very fine. You will need to do in batches. In a large bowl, combine graham crackers with melted butter. Spray a 9 x 13 baking dish with cooking spray and press half of the graham cracker into the bottom of the form, forming the crust. Bake for 15 minutes and let cool completely.
In a medium sized saucepan, over medium heat, cook together blueberries, 1/2 cup sugar, water, cornstarch and lemon zest, stirring constantly, until thickened. Set aside and let cool completely.
In another bowl, beat together cream cheese and the rest of the sugar until fluffy and sugar is completely dissolved. With a rubber spatula, slowly fold in Cool Whip.
Assemble dessert by placing half the cream cheese mixture inside the cooled crust. Spread slowly and evenly until crust is completely covered. Continue with cooled blueberry mixture over the cream cheese layer and top with remaining cream cheese mixture and then remaining graham cracker crumb mixture. Press crumbs softly into the cream cheese mixture.
Let sit overnight in the refrigerator before slicing into squares. Serve cold.