Bring a medium pot of water to a boil and cook the soba noodles for 4-5 minutes until tender, then drain and rinse with cold water.
Slice the chicken breast into thin, bite-sized strips and season evenly with the sea salt and black pepper.
Heat the toasted sesame oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken strips to the skillet and sear for 5-6 minutes, stirring occasionally, until golden brown and fully cooked.
Mince the garlic and grate the fresh ginger, then add them to the pan along with the broccoli florets and sliced red bell pepper.
Stir-fry the mixture for 3-4 minutes until the vegetables are vibrant and tender-crisp.
Add the cooked soba noodles and the tamari to the skillet.
Toss all ingredients together for 1-2 minutes until the noodles are heated through and everything is thoroughly coated in the sauce.