Heat the oil and add the onion and garlic, cooking and stirring about 5 minutes, until softened. Add the ground beef and cook, stirring to break up the chunks. Cook until no longer pink. Drain excess fat if there's a  lot. (It depends on what kind of ground beef you are using. Turkey will likely not have much if any to drain.)

Stir in the cumin and cook another minute, then stir in the tomato sauce and water. Bring to a simmer and cook, partially covered, 10-15 minutes. Take the cover off and simmer until it is as "dry" as you like it.