Combine first six ingredients; stir in 1/4 teaspoon salt., Sprinkle beef with pepper and remaining salt. Grill, covered, over medium heat or broil 4 in. from heat until meat reaches desired doneness (for medium-rare, a thermometer should read 135°; medium, 140°), 4-6 minutes per side. Top with tomato mixture. If desired, sprinkle with cheese.