Clean spinach in several changes of cold water and drain well. If using water spinach, trim and discard the bottom 2 inches of the woody ends. Cut remaining stems into 2 inch lengths and place in a bowl. Cut leafy top portions into 2 inch lengths and place in another bowl. If using regular spinach, trim and discard stems. Set aside.
Combine fish sauce, bean sauce, and palm sugar in a small bowl and set aside.
Heat oil in a wok, swirling to coat the surface, add the garlic and stir-fry for 10 seconds. Add the spinach stems, if using water spinach, toss to combine with the garlic and cook 1 minute. Add reserved fish sauce mixture, toss to combine with the garlic, and add leafy portions of water spinach, or all of regular spinach. Toss spinach quickly until it begins to wilt, then transfer to a serving platter. Serve warm.
c.1998, M.S. Milliken & S. Feniger, all rights reserved