Mix all spices and salt together until well blended. If you're using corn tortillas, you can begin warming them until pliable on a dry griddle or skillet or over a low flame on the stovetop. I like to keep all of them warm in a clean kitchen towel.
Heat a large skillet over medium heat. Add the beef to the skillet and cook, breaking up beef into small pieces (I like to do this by pressing against the meat with a slotted spoon), just until cooked through. If there's any liquid in the pan, drain before proceeding.
Dissolve the corn starch in ¾ cup cold water. Add the spice mixture to the meat and cook over medium heat for a minute. Pour the water and dissolved arrowroot over the beef and cook until thickened, stirring occasionally.
Serve with corn tortillas, guacamole, pico de gallo, shredded cheese, refried black beans, cilantro-lime slaw, and/or shredded lettuce.