Slice the beef sirloin into very thin strips against the grain and season with sea salt and black pepper.
In a small bowl, whisk together the coconut aminos, toasted sesame oil, and arrowroot powder until the mixture is smooth.
Heat the avocado oil in a large stainless steel skillet or wok over medium-high heat until it is shimmering.
Add the beef strips in a single layer and sear without moving for 2 minutes until a brown crust forms, then flip and cook for 1 more minute.
Remove the beef from the skillet and set it aside on a clean plate.
Add the broccoli florets to the same skillet with two tablespoons of water, cover with a lid, and steam for 2-3 minutes until bright green.
Remove the lid, add the minced garlic and grated ginger, and sauté for 30 seconds until fragrant.
Return the beef and any accumulated juices to the skillet, pour the sauce over the mixture, and toss for 1 minute until the sauce thickens and coats everything.
Serve immediately topped with a sprinkle of sesame seeds.