Mix minced onion, salt, chili powder, cornstarch, cumin, red pepper flakes, cayenne pepper, dried minced garlic, and oregano in a bowl.
Heat a large skillet over medium-high heat. Crumble ground beef into the hot skillet. Cook and stir until the beef is completely browned, 7 to 10 minutes. Drain and discard any excess grease.
Return ground beef to heat. Pour seasoning mixture and water over the beef; stir to combine. Bring to a simmer and cook until the moisture absorbs into the meat, about 5 minutes.