Heat a wok until smoking. Add half the peanut oil and, when hot, stir-fry the snapper in two batches until golden and just cooked through, then remove. Wipe the wok clean.
Heat the remaining oil in the wok until just smoking. Stir-fry the ginger, garlic, spring onions and chilli until fragrant, then add the asparagus and snow peas and stir-fry until just tender. Return the snapper to the wok with the chicken stock, oyster sauce, soy sauce and sugar, toss together and bring to the boil. Fold in the enoki mushrooms and spoon onto a large plate to serve.