Brown the ground beef over medium heat. (Optional - whisk the corn starch into the water) Combine all spices in a small bowl while the meat is browning.
Drain the ground beef, place it back in the pan, add water mixture and all spices to the pan.
Simmer over medium low for a few more minutes, until most of the water has evaporated and the sauce has thickened slightly.
Serve in tortillas with your favorite taco toppings!