The morning before, make curry paste: Trim grassy tops from lemongrass stalks, then trim roots. Peel off woody outer layers and discard. Thinly slice stalks crosswise and transfer to a food processor. Add shallots, garlic, curry powder, and salt, and pulse into a coarse paste.
About an hour before dinner, let someone prep the rice while you make the curry with a couple of guests (each of you will make 1 batch): Divide oil, curry paste, and chiles between 3 large Dutch ovens or heavy pots. (If that’s not possible, set one-third of ingredients aside and make 2 pots of chicken first; pour into a large roasting pan and keep warm in a 200° oven while you cook the third batch.) Start with a cold pan and cold oil to keep the garlic in the paste from burning. Fry paste and chiles over medium heat, stirring, until mixture is very fragrant, about 5 minutes.
Divide chicken wings, oyster sauce, and fish sauce between pots and stir to coat wings. Add 1 cup water to each pot and bring to a boil over high heat. Cook, uncovered, stirring often, until sauce is reduced to a loose paste (oil will separate) and wings are tender, 20 to 30 minutes.
Top with green onions and cilantro. Serve hot, with rice and Cucumber and Shallot Pickle, and a bowl for the bones. *Ask your butcher to trim the tips, or buy “party wings,” which are the first and second joints, cut apart.