Hea a wok with oil and fry the ginger and
garlic until golden and fragrant. Add chili paste and fish curry powder,
lemon grass and curry leaves. Fry until the mixture is fragrant. Add
seasoning, crabs and the long beans. Toss to combine well. Cover with a
lid and cook for about 4 minutes. Add onion and stir-fry until the sauce
thickened. Serve immediate while still hot.