Slice the flank steak against the grain into thin strips and season with sea salt and black pepper.
In a small bowl, whisk together coconut aminos, toasted sesame oil, rice vinegar, and arrowroot powder to create the glaze.
Heat avocado oil in a large skillet or wok over high heat until shimmering.
Add the beef strips in a single layer and sear for 2 minutes until browned, then remove from the pan and set aside.
Add the broccoli florets and a splash of water to the pan, covering for 2 minutes to steam-fry until bright green.
Stir in the minced garlic and grated ginger, sautéing for 30 seconds until fragrant.
Return the beef to the pan and pour the glaze over the mixture, tossing constantly for 1 minute until the sauce thickens and coats everything.
Garnish with sesame seeds and serve immediately.