1. In a large nonstick skillet, warm the oil over medium-high heat until hot but not smoking. Stir in the eggplant, bell peppers, zucchini, sweet potato, onion and garlic. Stir-fry until the vegetables begin to soften, about 10 minutes. Stir in 2 tablespoons each of the basil and mint. Reduce the heat to medium-low, cover, and cook until the vegetables are very tender, about 10 minutes.
2. Remove the large pieces of red bell pepper from the skillet and place them in a food processor. Add the 0.75 cup tomato juice and 3 of the canned tomatoes to the processor and process to pur
3. Return the pur tomatoes, the vinegar, black pepper, sugar, and red pepper flakes, and bring to a boil over medium-high heat, breaking up the tomatoes with a spoon. Reduce the heat to low and simmer while you cook the pasta.
4. Bring a large pot of water to a boil. Add the ziti and cook until al dente, 10 to dozen minutes, or according to package directions.
5. Drain the pasta in a colander and transfer to individual dinner plates. Spoon the ratatouille sauce over the ziti. Sprinkle the remaining basil and mint on top and serve.