1) For the dressing: Whisk the miso, water, vinegar, soy sauce, ginger, and chilli, to taste, in a bowl. Gradually whisk in the oil, starting with a few drops and then adding the rest in a steady stream to make a smooth, slightly thick dressing. Serve or refrigerate in a tightly sealed container for up to 3 days.
2) For the vegetables: Pour 2.5cm or more of water in a wok or skillet and bring to a boil over medium-high heat. Place the vegetables in a bamboo or collapsible steamer. Set the steamer over the boiling water, cover, and cook for 5 to 8 mins, or just until the vegetables are crisp tender. Serve warm or at room temperature with the dressing.