Cut the chicken breast into small, bite-sized cubes and season evenly with sea salt and black pepper.
Heat the avocado oil in a large non-stick skillet or wok over medium-high heat until it begins to shimmer.
Add the chicken to the skillet in a single layer and sear without moving for 3 minutes to develop a golden crust, then toss and cook for another 2-3 minutes until finished.
Remove the chicken from the pan and set it aside on a plate.
In the same skillet, add the sesame oil, minced garlic, and grated ginger, sautéing for about 30 seconds until the aromatics are fragrant.
Add the cooked brown rice and the frozen peas and carrots to the pan, spreading the rice out and pressing down firmly with a spatula.
Let the rice fry undisturbed for 2 minutes to achieve a crispy texture, then stir and fry for another minute.
Return the cooked chicken to the skillet, drizzle with tamari, and toss everything together for 1 minute to glaze.
Remove from heat and garnish with sliced scallions and toasted sesame seeds before serving.