Heat the oil in a large saucepan. Sizzle the green onion whites (save some for garnishing), pepper, chilli paste and garlic for 5-8 mins until soft and fragrant. Add the thyme, curry powder and spices, then cook for 2 min more. Stir in the tomatoes, then cook for 2 mins to soften slightly.
Tip in all the beans and the coconut milk. Simmer for 10 mins. Turn off the heat and stir in the lime juice and some seasoning. Ladle into bowls and scatter with remaining green onions just before serving.