Slice the flank steak against the grain into very thin strips to ensure maximum tenderness.
In a small bowl, whisk together the coconut aminos, minced ginger, minced garlic, and arrowroot powder until smooth.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the beef strips in a single layer, seasoning with sea salt and black pepper, and sear for 2 minutes until browned.
Remove the beef from the pan and add the broccoli florets with a tablespoon of water; cover and steam for 3 minutes.
Return the beef to the pan, pour the sauce over the mixture, and toss constantly for 1 minute until the sauce thickens.
Remove from heat, drizzle with sesame oil, and garnish with sesame seeds before serving.