Cook the soba noodles in a large pot of boiling water according to package directions, typically for about 5 minutes, until just tender. Be careful not to overcook.
Drain the noodles immediately and rinse thoroughly under cold running water to stop the cooking process and remove excess starch.
Transfer the cooled noodles to a large serving bowl.
Drizzle with 1 teaspoon (5 ml / 0.2 fl oz) of the toasted sesame oil and toss gently to prevent sticking.
Add the julienned red bell pepper, sliced napa cabbage, and sliced scallions to the bowl with the noodles.
In a small bowl or jar, whisk together the rice vinegar, minced ginger, sugar, and a pinch of salt and pepper.
While whisking continuously, slowly stream in the remaining toasted sesame oil until the dressing is emulsified and well blended.
Pour the dressing over the noodle and vegetable mixture.
Toss everything together until well combined.
Serve immediately or chilled.
Rinse the soba noodles under cold water immediately after draining. This stops the cooking process and removes excess starch, preventing them from becoming gummy.
