Step 1Soften tomatoes in hot water 15 minutes. Drain, then blend with garlic, lemon juice, mayonnaise and cheese in blender until smooth. Set aside.
Step 1Toss mushrooms, eggplants, zucchini, yellow squash and onion with oil, garlic and salt and pepper to taste. Divide vegetables into 2 batches. Place first batch on grill rack over medium-high heat and grill, turning over halfway, until softened and slightly charred but still intact, about 10 minutes. (Vegetables can also be broiled; keep an eye on them and turn them over halfway through.) Lay flat on baking sheet to cool. Repeat with second batch. (Vegetables can be refrigerated for later use at this point).
Step 2Spread bread slices with Sun-Dried Tomato Spread. Top half bread slices with grilled vegetables, lettuce and tomato slices, dividing evenly. Top with remaining bread slices. Cut in half and serve.