In a bowl, marinate the steak with ground cumin and salt for 5-7 minutes. Set aside while you prepare the vegetables.
Add 1 tablespoon of oil to a cast-iron skillet and let it heat all the way through. Sear the steak for about one minute on each side and remove to a plate.
Add another tablespoon of oil and onion—Cook for about 5 minutes or until they are wilted and begin to brown.
Add garlic and red wine vinegar. Cook for another 30 seconds.
Add tomatoes and cook for another 2 minutes.
Return the steak to the pan. Add soy sauce and toss to combine until the steak is completely cooked. Garnish with cilantro and serve warm over rice.