For the sour cream sauce: Soak the cashews in filtered water for 1 hour and drain. Blend the cashews, oil, lemon juice, vinegar, salt and 1/2 cup filtered water in a high-speed blender until very smooth and creamy, about 30 seconds. If necessary, scrape down the sides of the blender jar with a spatula and blend again. The sauce will keep for up to 5 days in a covered container in the refrigerator.
For the ratatouille filling: Heat the oil in a large saute pan over medium heat. Cook the onions and garlic, stirring occasionally, until they are lightly caramelized, about 6 minutes. Add the eggplant and cook, stirring occasionally, until slightly softened, about 5 minutes. Stir in the peppers and zucchini and continue to cook until slightly softened, about 5 minutes. Add the tomatoes, parsley, basil, thyme, marinara sauce, vinegar, crushed red pepper and some salt and pepper and cook until the mixture is cohesive with each vegetable retaining its individual character, 5 to 7 minutes.
Mix the ratatouille well and place a large scoop on a fresh lavash or tortilla. Spoon a healthy dollop of the sour "cream" sauce on top and fold over both sides of the wrap to close it. Put a small spoonful of the sour "cream" sauce on top of the sealed wrap and sprinkle with fresh chopped parsley.