Sprinkle the steak with the chili powder, 1/2 teaspoon of the salt and cumin. Spray a large nonstick skillet with cooking spray and set over high heat. Add the steak and cook until browned, about 5 minutes. Turn the steak and cook about 5 minutes longer for medium-rare. Transfer the steak to a cutting board. Let stand 5 minutes. Cut the steak diagonally across the grain into paper-thin slices.
Meanwhile, combine the black beans, cilantro, lime juice, oil, tomatoes, garlic, jalapeno and the remaining 1/4 teaspoon salt in a large bowl and toss to coat well. Evenly divide the steak slices among the tacos. Top each taco evenly with the tomato mixture.
Per Serving: 335 Cal; 25 g Protein; 12 g Tot Fat; 3 g Sat Fat; 5 g Mono Fat; 33 g Carb; 7 g Fiber; 4 g Sugar; 115 mg Calcium; 4 mg Iron; 512 mg Sodium; 29 mg Cholesterol