Slice the flank steak against the grain into thin, bite-sized strips and season with sea salt and black pepper.
Mince the garlic cloves and finely grate the fresh ginger, setting them aside for the 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 2-3 minutes until browned and caramelized, then remove from the pan and set aside.
In the same pan, add the broccoli florets and a splash of water, covering with a lid for 2 minutes to steam until bright green and tender-crisp.
Remove the lid, add the minced garlic and grated ginger, and sauté for 1 minute until the aromatics are fragrant.
Return the beef to the pan and pour in the coconut aminos and toasted sesame oil.
Toss all ingredients together for 1-2 minutes until the sauce coats the beef and broccoli evenly.
Garnish the dish with sesame seeds and serve immediately while hot.