Place steak on a dinner plate, spoon 1 tbsp vinegar over top and turn several times to coat. Let stand 10 minutes.Meanwhile, prepare sauce: In a small bowl, whisk together all sauce ingredients and set aside.Heat oil in a large nonstick skillet on medium-high. Tilt skillet to coat bottom lightly. Cook steak for 4 minutes per side or to desired doneness. Place on a cutting board and let stand for 5 minutes before thinly slicing.Warm tortillas according to package directions. Top each tortilla with equal amounts of lettuce, carrots, onion and cucumber. Divide steak among tortillas and sprinkle with cilantro. Spoon sauce over top, dividing evenly. Wrap to serve as a sandwich or serve open-faced.