Combine the lemon zest, lemon juice, and 1/2 tablespoon of the olive oil in a small bowl; set aside. Turn on the exhaust fan and heat a heavy 12-inch skillet or large wok over high heat for 2 minutes. When the pan is hot, pour in the remaining 2 tablespoons olive oil, and a few seconds later, add the asparagus, garlic, shallot, and chile flakes. Season well with salt and pepper. Cook, shaking the pan often, until the asparagus begins to brown and starts to shrivel slightly, 3 to 4 minutes. Reduce the heat to medium low, carefully add the water (it will steam), and cover the pan with the lid ajar. Cook until the asparagus is just tender, 3 to 4 minutes. (If the water evaporates before the asparagus is done, add more, 1 tablespoon at a time.) Drizzle the lemon mixture over the asparagus. Season to taste with salt and pepper. Transfer the asparagus to a small serving dish and top with the Parmesan curls. Serve immediately.