Heat the avocado oil in a large cast-iron skillet or wok over medium-high heat.
Season the diced chicken breast with sea salt and black pepper, then add to the skillet and sauté until golden brown and cooked through.
Remove the chicken from the skillet and set aside on a plate.
Add the sesame oil to the same skillet, then stir in the diced white onion, minced garlic, and grated fresh ginger, sautéing for 2 minutes until aromatic.
Add the frozen peas and carrots to the skillet and cook for another 3 minutes until tender.
Push the vegetable mixture to the sides of the pan and crack the egg into the center, scrambling it quickly until fully set.
Incorporate the chilled jasmine rice and the cooked chicken back into the skillet, breaking up any clumps of rice with a spatula.
Pour the tamari over the rice and toss everything together, allowing the rice to fry and slightly crisp for 3-4 minutes.
Garnish with thinly sliced green onions and serve immediately.