To make the salad:
Position the rack in top third of the oven and preheat to 450 degrees. Spray a large heavy baking sheet with the nonstick vegetable oil spray. Combine the eggplant, peppers, garlic and oil in large bowl. Toss well. Transfer to the prepared baking sheet. Bake until the eggplant is brown and the vegetables are tender, stirring every 10 minutes, about 50 minutes. Remove the garlic and reserve. Scrape the vegetables and all the pan juices into a bowl.
Combine the vinegar, cumin, salt, pepper and cayenne in a food processor. Peel the roasted garlic and add to the processor. Puree until smooth. Toss the vegetable mixture with one-fourth cup of the garlic dressing. Cool, tossing occasionally. (It can be made 1 day ahead. Cover and chill the vegetables and the remaining dressing separately. Bring to room temperature before serving.)
Mound the salad in the center of a large platter. Surround with the pita wedges. Serve, passing the remaining dressing and the sesame spread separately.
To make the sesame spread:
Blend the margarine, sesame seeds and salt in small bowl. (It can be prepared 2 days ahead. Cover and refrigerate. Bring to room temperature before serving.)
Makes 8 servings