Place water and sugar in a saucepan and place on high heat.
Once liquid begins to boil add tamarind paste and lower heat to simmer.
Stir until paste has dissolved.
Add soy sauce, garlic, ginger, salt and red pepper flakes.
Stir until ingredients are combined, then raise the heat to medium.
Reduce sauce by one third.
Dissolve corn starch in a small bowl and then add to sauce.
Stir until sauce thickens, then cover and set aside.