Step 1

Heat a wok on high till smoking, then swirl in oil. Heat till shimmering, about 30 seconds, then add mustard seeds. Stir to coat with oil. When seeds begin to pop, press a lid down in the wok for 10 seconds until popping begins to subside. Remove lid and add garlic, stirring vigorously to evenly distribute heat and keep mustard seeds from burning, until garlic is fragrant (about 30 seconds).

Step 2

Add spinach and stir with tongs to coat in oil. Stir fry until spinach begins to wilt, 1 to 2 minutes, then add rice wine and cook for one minute longer as a thin sauce forms. Remove wok from heat and add rice vinegar and salt to taste. Serve immediately, with rice.