Arrange a cooling rack over a baking sheet. Preheat oven to 300°F.
Season tomatoes with salt, pepper and a light sprinkle of sugar. Roast tomatoes 45 minutes to 1 hour, until caramelized. Remove tomatoes to a plate and reserve. Raise the oven temp to 450°F.
Cut tops and trim bottom of eggplant. Cut into slices 1/2-inch thick, brush with EVOO and season with salt and pepper. Roast 15 minutes, remove and cool.
Slice red onion into thin rings and dress with lime juice, a drizzle of oil and season with salt and pepper.