In 10-inch skillet, heat oil over med-high heat until very hot but not smoking. Sprinkle steaks with salt and pepper. Add steaks to skillet and cook 8-10 min, turning once for med-rare or desired doneness. Transfer steaks to cutting board; keep warm.
Reduce heat to medium. Add onion to drippings in skillet and cook, stirring until browned and tender, about 5 minute Add vinegar, chopped rosemary, and 2 tbsp water, stirring until browned bits are loosened from bottom of skillet. Stir in tomatoes and beans; cook, stirring ocasionally until heated through - about 2 minute.
Thinly slice steaks and serve with tomato and bean mixture. Garnish with rosemary leaves.