Bring a medium pot of water to a boil over high heat; Turn off the burner and completely submerge the bean threads in the water for 15 minutes.
While the bean threads are soaking prepare the vegetables. Peel and remove the seeds from the cucumbers. Cut into a small dice. Cut the tomatoes in half, remove the seeds. Cut into a small dice. Remove the core from the cabbage and thinly slice. Thinly slice the spring onions on the diagonal.
Add prepared vegetables to a large bowl.
Meanwhile, whisk together the vinaigrette ingredients in a small bowl.
When the bean threads are done, drain and rinse well in cold water,Transfer the bean threads to the bowl of vegetables and toss.
Add the vinaigrette and toss, taste and adjust the seasoning.