Brush the eggplants, onions, peppers and tomatoes with 1/3 cup oil. Grill the vegetables until the skins blacken and the vegetables are tender, turning every few minutes to ensure even cooking. Place in a container with a lid and let steam for 10 for 15 minutes. When cool enough to handle, peel the eggplants, peppers and tomatoes. Peel away the outer layer of the onions. Cut vegetable lengthwise into strips about 1 1/2 inches wide. Transfer to a bowl and mix in the vinegar, garlic and 1/4 cup oil. Season with salt and toss to mix well. Serve at room temperature on grilled bread.