Slice the chicken breast into thin, even strips for quick and uniform cooking.
Mince the garlic clove and finely grate the fresh ginger.
In a small jar, combine the tamari, toasted sesame oil, red pepper flakes, and water; shake well to emulsify the sauce.
Heat the avocado oil in a large skillet or wok over medium-high heat until it begins to shimmer.
Add the chicken strips to the hot pan, spreading them out to ensure a golden-brown sear on all sides, cooking for about 5 minutes.
Transfer the cooked chicken to a plate and set it aside to keep it tender.
Add the broccoli florets to the same skillet with the tablespoon of water, cover with a lid, and steam for 2-3 minutes until bright green.
Remove the lid, add the garlic and ginger to the broccoli, and sauté for 30 seconds until the aroma fills the kitchen.
Return the chicken to the pan and pour the prepared sauce over the mixture, tossing everything together for 1 minute until glazed and thickened.
Serve the stir-fry immediately over a warm bed of cooked white rice.