Slice the chicken breast into bite-sized strips and season with sea salt and black pepper.
Chop the red bell pepper, zucchini, and white mushrooms into uniform pieces for even cooking.
Heat the olive oil in a large skillet or wok over medium-high heat until shimmering.
Add the chicken to the pan and sear until golden brown and cooked through, then remove and set aside.
In the same pan, add the sesame oil, minced garlic, and grated ginger, sautéing for 30 seconds until fragrant.
Toss in the peppers, zucchini, and mushrooms, stir-frying for 5-7 minutes until the vegetables are tender-crisp.
Return the chicken to the pan, drizzle with tamari, and toss everything together to coat well.
Serve immediately, garnished with a generous sprinkle of toasted sesame seeds for a satisfying crunch.