Add ground beef to a large pan or Dutch oven with about ½ cup of water and the salt. Set burner to medium heat and as the pan warms, work with the ground beef, breaking it up into small pieces. A potato masher works well for this. Continue to break up the beef as it cooks, and when water is evaporated and there is no longer any pink in the beef, drain excess grease. If necessary, more water mayb be added by the quarter cupful if the beef is still pink by the time the water has evaporated. If the heat is at medium and the beef is cooking slowly, it should be fine as is. Add the cumin and pepper, and if using, a pinch of red pepper flakes and stir.
While beef is cooking, add tomatoes, onion in a blender with a splash of water if needed to get blender going, and mix until no chunks remain. The goal is to have this mixture at the ready; when the beef is cooked and the water is gone and the excess fat drained, you’ll want to immediately add the tomatoe mixture right after cumin and pepper are stirred in.
Spread the beef apart in the pan and push it up against the edges. Add in the tomato mixture at once to center of pan. It will dance and sizzle. Cook, stirring the beef into the tomatoe mixture now and then, and then pushing the beef back up to the sides until almost all the liquid is gone. Stir together final time. Taste for seasoning. Add salt and pepper if desired. Immediately remove from heat.
This recipe is best if beef isn’t drained after the intital cooking till “bone” dry. Leave a little of the fat in; fat after all, carries flavor.