To make marinade, combine ingredients, slowly adding olive oil and stirring briskly to combine well. Set aside.Preheat grill or broiler.Cut eggplant lengthwise into four ½-inch-thick slices to resemble steaks. Brush “steaks” with marinade.Grill or broil eggplant for 2 minutes on each side, or until tender but not soft. Remove from heat and place 1 steak on each serving plate.Place chickpeas, red peppers, feta, black olives and oregano in small bowl. Season to taste with salt and pepper, and stir to combine well. Add some marinade and stir again. Toast or grill pita bread and cut into pie-shaped wedges and set aside.Spoon 1 or 2 scoops of pepper-olive mixture on eggplant steak with some mixture pooling onto plate. Sprinkle with balsamic vinegar, place several pita wedges on plate and garnish eggplant with several sprigs fresh oregano. Repeat with remaining ingredients until used up, making sure pepper-olive mixture spills over top of eggplant and onto plate. Serve immediately.