I use a slurry to make my homemade ground beef saucy. Fill a shaker cup with ½ cup cold water or beef/vegetable stock. Add 1 ½ tablespoons all-purpose flour, masa or whole wheat flour to the liquid and cover it. Shake for at least 30 seconds. With the skillet on low heat, slowly stream in the slurry while stirring with a wooden spoon. Stir often and cook over low for about 10 minutes.
Toss the tomatoes, onion, cilantro and lime juice together in a bowl. Season with a pinch of salt and pepper