1.Cook potatoes in a saucepan of boiling salted water for 8-10 minutes until just tender. Drain. Cool. Cut into chunks.
2.Heat oil in a wok or large saucepan on high. Add paste and cook, stirring, for 1 minute until fragrant.
3.Blend in coconut milk, sauce, juice and sugar. Bring to boil. Reduce heat. Simmer for 10-15 minutes until thickened slightly.
4.Add fish, beans and potatoes. Cook for 4-5 minutes, stirring, until fish is cooked through. Stir in coriander and onions.
5.Top with coriander leaves, bean sprouts and chilli, and serve with rice.
Snake beans are popular in Asian cooking. The pods are olive green, round, about 90cm long and 5-8mm wide. They are picked when young and crisp with soft seeds. If they are unavailable, use green beans. This dish would also be delicious with mixed seafood.