For steak, heat grill pan over medium heat for 5 minutes. As pan heats, rub steak with salt. Place steak into pan; cook 6-8 minutes or until grill marks appear. Turn steak over and cook an additional 6-8 minutes or until medium done. Remove from heat; transfer steak to cutting board.
As steak cooks, prepare salsa. Chop parsley. Combine parsley, oil, vinegar, salt, garlic, and cayenne pepper in small bowl. Spoon 3 Tbsp salsa evenly over steak. Let stand 10 minutes.
While steak stands, prepare salad. Thinly slice lettuce and cut tomatoes in half lengthwise; place lettuce and tomatoes into large serving bowl. Pour remaining salsa over salad and toss gently.
To serve, divide salad among serving plates. Thinly slice steak and arrange over top of salad.
