Slice the flank steak against the grain into thin strips and season evenly with sea salt and black pepper.
In a small bowl, whisk together the coconut aminos, minced garlic, and grated fresh ginger 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 2 minutes until deeply browned, then remove from the pan and set aside.
Add the broccoli florets to the same pan with a tablespoon of water, cover with a lid, and steam for 3 minutes until tender-crisp.
Return the beef to the pan, pour in the prepared sauce mixture, and toss everything together for 1 minute until the sauce coats the ingredients.
Remove from heat, drizzle with toasted sesame oil, and garnish with sesame seeds before serving.