In a small glass bowl, whisk together the tamari, rice vinegar, honey, grated ginger, minced garlic, and toasted sesame oil to create the sauce.
Pat the chicken breast dry with a paper towel, cut into 1-inch cubes, and toss in a bowl with arrowroot powder until every piece is lightly coated.
Heat the avocado oil in a large non-stick skillet over medium-high heat and sear the chicken for 5-6 minutes until golden brown and cooked through.
Add the broccoli florets to the skillet along with two tablespoons of water; cover with a lid for 2 minutes to steam the broccoli until it is tender-crisp and vibrant green.
Remove the lid and pour the prepared sauce over the chicken and broccoli, stirring constantly for 1 minute until the sauce reduces into a thick, glossy glaze.
Transfer the cooked white rice to a bowl and top with the glazed chicken and broccoli.
Garnish the dish with red pepper flakes, sesame seeds, and sliced green onions before serving.