Whisk together the corn syrup and water in a small bowl, then place into the microwave for 30 seconds.
Place each color of glitter in a separate bowl and set up a “glitter fortune cookie making station”.
Use a small pastry brush or food-safe paint brush to brush the warm corn syrup on one corner of the fortune cookie, then sprinkle with the edible glitter.
Repeat this step on the other corner with the same, or a different color, glitter.
Repeat the two steps above until all of the fortune cookies have been "glittered".
Notes
Do not make these fortune cookies ahead of time or the area with the corn syrup and glitter will get soggy! I recommend making them at most 8 hours in advance.