Slice the flank steak against the grain into thin, bite-sized strips and season evenly with sea salt and black pepper.
In a small glass bowl, whisk together the coconut aminos, toasted sesame oil, minced ginger, and water to create the stir-fry sauce.
Heat the avocado oil in a large skillet or wok over medium-high heat until it begins to shimmer.
Add the beef strips in a single layer and sear for approximately 2 minutes until browned and caramelized, then remove from the pan and set aside.
Add the broccoli florets and minced garlic to the same pan with a splash of water, covering with a lid for 2 minutes to steam until tender-crisp.
Return the beef to the pan, pour the prepared sauce over the mixture, and toss for 1-2 minutes until the sauce thickens and coats the ingredients.
Garnish with toasted sesame seeds and serve immediately.