Preheat the oven to 350 degrees F. Line a 9x9 square baking pan with parchment paper.
To a food processor, add in graham crackers, then pulse as you slowly add in the butter, water, and granulated sugar. The crust should be a little wet and slightly crumbly. Pack crust into baking pan and bake for 10 minutes. Set aside to cool.
While the crust bakes, make the orange vanilla portion. In a large mixing bowl, whisk together the cornstarch, orange juice, orange zest, lemon juice, vanilla, salt, and eggs until combined. Slowly work in the powdered sugar, then let sit until crust is ready.
When the crust is done baking, remove from the oven and let cool slightly for 15 minutes. Drop oven temperature to 325˚F and pour filling into pan. Bake for 16 minutes, or until the center of the bars are just set and not wet. Be cautious not to overcook, as the bars will become eggy. Let the pan cool for four hours to set, then dust with powdered sugar, slice and serve.