Cook the soba noodles according to package directions.
Drain well, return to the hot pan, and cover to keep warm.
Meanwhile, pour the toasted sesame oil into a large wok or skillet and preheat over medium-high heat.
Add the broccoli florets and sweet pepper strips.
Cook and stir for 3 minutes.
Add the 6 bias-sliced green onions to the wok.
Continue to cook and stir for 1 to 2 minutes more, or until all the vegetables are crisp-tender.
Stir in the plum sauce, rice vinegar, soy sauce, and crushed red pepper.
Toss everything to coat the vegetables and allow the sauce to heat through.
Add the warm soba noodles to the wok with the vegetables and sauce.
Toss gently until everything is well combined.
Serve immediately, sprinkling each portion with toasted almonds and an extra garnish of sliced green onions, if desired.
Rinse soba noodles under cold water immediately after draining. This removes excess starch and stops the cooking process, preventing them from becoming gummy before you add them to the stir-fry.