Brush eggplant with 1 tablespoon oil. Season eggplant and beef steaks with pepper. Place steaks in center of grid over medium, ash-covered coals; arrange eggplant around steaks. Grill steaks, covered, 10 to 14 minutes (over medium heat on preheated gas grill, covered, 12 to 16 minutes) for medium rare (145°F) to medium (160°F) doneness, turning occasionally. Grill eggplant 6 to 8 minutes (gas grill times remain the same) or until tender.
Meanwhile, combine tapenade, remaining 1 tablespoon oil and chopped oregano in small bowl; set aside.
Carve steaks into thin slices. Season beef and eggplant with salt, as desired. Place eggplant slices on plates; layer evenly with beef, tomato and zucchini. Spoon tapenade mixture on top. Garnish with oregano sprigs, if desired.