In a large soup pot, saute the onions in the oil for about 5 minutes. Stir in the eggplant, sweet potatoes, and curry paste. Add the pineapple juice, water, and salt. Bring to a boil, and then reduce the heat and simmer for 5 minutes.
Add the cauliflower and green beans and cook for another 5 minutes. Stir in the peppers, tomatoes, lime juice, and cilantro. Simmer until the vegetables are tender, about 10 minutes.
Serve on rice with a few fresh herb sprigs and, if desired, some chopped peanuts.