Slice the sirloin steak into thin, bite-sized strips against the grain and season with sea salt and black pepper.
In a small bowl, whisk together the coconut aminos, toasted sesame oil, rice vinegar, minced garlic, and grated ginger.
Heat the avocado oil in a large skillet or wok over medium-high heat until shimmering.
Add the beef strips in a single layer and sear for 2-3 minutes until browned, then remove from the pan and set aside.
Add the broccoli florets to the same pan with a splash of water, cover, and steam for 3 minutes until tender-crisp.
Return the beef to the pan, pour the sauce over the mixture, and toss for 1 minute until the sauce thickens and coats everything.
Garnish with sesame seeds and serve immediately.