Cut your steak into 4-inch wide strips. Mix the garlic powder, salt and pepper together in a small bowl and sprinkle evenly over both sides of the meat.
Dust the meat with the flour evenly over both sides. Shake off any excess and set the meat aside.
Heat a skillet over medium-high and add the oil. Heat until just shimmering and add the meat in a single layer. It should sizzle immediately. Cook on one side until golden brown--about 4 minutes, then turn and cook 4 minutes or so on the other side.
Turn off the skillet and transfer the meat to your slow cooker. If you used your dutch oven to sear the meat, just add the ingredients in with the meat.
To the meat, add the crushed garlic, tomatoes, water, onions and peppers. Stir to combine, cover and cook on low 6 hours or until the meat is very tender and almost falling apart.
If cooking in the oven, bake at 350 for about 2 hours (check it after one hour and add more tomato juice if it's cooking down too much) or cook until the meat is very tender.
Serve warm with green beans and mashed potatoes.