Slice the shallots thin and dry on paper towels. Heat oil in a wok on medium to high heat and add the shallots. Cook, stirring regularly, until the shallots have caramelized. Transfer with a slotted spoon to paper towels.
Mix together the mirin, soy and fish sauce and set aside. Drain most of the oil except for a small coating in the bottom of the wok. Add the garlic, stir frying until fragrant. Add the zucchini and cook until browned slightly, then add the enoki mushrooms. Stir until the mushroom have just started to soften, then add the sauce. Cook until the sauce is almost completely reduced.