Pat the chicken breast dry and cut into small, bite-sized cubes, then season with sea salt and black pepper.
Heat a large non-stick skillet or wok over medium-high heat and add half of the toasted sesame oil.
Add the chicken to the pan and sear for 4-5 minutes until golden brown and cooked through, then remove and set aside.
In the same pan, crack the egg and scramble quickly until just set, then push to the side of the pan.
Add the remaining sesame oil along with the minced garlic, grated ginger, diced carrots, and peas, sautéing for 2 minutes until fragrant.
Add the chilled jasmine rice to the pan, breaking up any clumps with a spatula, and stir in the tamari.
Return the cooked chicken to the pan and toss everything together for 2-3 minutes until the rice is heated through and slightly crisp.
Thinly slice the green onion and garnish the fried rice before serving hot.