Add water, sugar and vinegar to a small sauce pan.

Cook over medium heat for a couple of minutes until the sugar dissolves. Stir consistently with a whisk.

Reduce heat to low and add ginger, garlic and chili flakes.

In a small bowl combine corn starch and enough cold water to create a slurry.

Add the cornstarch mixture to the sauce and simmer for another minute or two until it begins to thicken.

Remove from heat, allow to cool and serve.