The vegetable-feta mixture here absorbs loads of tangy flavor from the herbed balsamic vinegar marinadebe sure to prepare it first and let it stand while you grill the eggplant. Since you have the barbecue going anyway, grill some green bell peppers to add to the sandwiches.
1. Make salad: In medium bowl, combine cheese, tomatoes, olives, onion, vinegar, parsley, garlic and oil. Mix well. Let stand 20 minutes, stirring occasionally. Stir in cucumber, salt and pepper and let stand 10 minutes.
2. Meanwhile, prepare a charcoal fire or preheat gas grill on high. Brush both sides of eggplant slices with oil and grill, turning once, 15 to 20 minutes. (Alternatively, bake eggplant at 400°F until tender, about 25 minutes.) Transfer to a plate; season with salt and pepper.
3. In large skillet, warm each tortilla over medium heat just until soft and flexible, about 1 minute per side. Arrange 2 or 3 eggplant slices down center of each tortilla, overlapping slightly. With slotted spoon (to avoid getting too much liquid), spoon salad over eggplant, dividing equally. Fold bottom end of tortilla partially over filling, then roll into a bundle and serve.