1. Preheat grill on high. Meanwhile, whisk vinegar, lemon juice, salt, and pepper in a large bowl. Whisking constantly, slowly drizzle in 1 Tbsp. of the oil; continue whisking until the dressing is uniform. Set aside.
2. Rub the remaining 1 Tbsp. oil over the steak, then sprinkle with rub evenly and rub it into the meat. Grill steak covered over high heat 4 to 6 minutes per side, depending on desired doneness. Transfer to a plate, cover loosely with foil, and let rest for about 10 minutes. Slice steak very thinly,on the bias (diagonally across the grain)and arrange the slices neatly in the center of a large serving platter.
3. Whisk the dressing to recombine. Add tomatoes, mango, and most of the basiland toss gently to coat with dressing. Arrange the salad around the sliced steak,sprinkle with the remaining basil, and serve immediately.
Source: fresh magazine July, August 2010