Place soy chunks in a bowl and cover with boiling water; let soak for 10 minutes until softened, then drain and squeeze out all excess moisture.
Heat avocado oil in a large skillet or wok over medium-high heat.
Add the rehydrated soy chunks to the pan and sauté for 5-7 minutes until the edges are golden brown and slightly crispy.
Toss in the champignons and green beans, cooking for another 5 minutes until the mushrooms release their moisture and the beans are tender-crisp.
Stir in the garlic and fresh ginger, cooking for 1 minute until fragrant.
Whisk together the tamari, toasted sesame oil, and rice vinegar in a small bowl, then pour the mixture over the stir-fry.
Season with sea salt and black pepper, tossing everything together for 2 minutes to coat thoroughly.
Remove from heat and garnish with sesame seeds before serving.