Slice the flank steak against the grain into thin, bite-sized strips and season with sea salt and black pepper.
In a small bowl, whisk together the coconut aminos, toasted sesame oil, minced ginger, and minced garlic to create the stir-fry sauce.
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 minutes per side until browned and caramelized, 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 for 2 minutes to steam until tender-crisp and bright green.
Return the beef to the pan and pour the sauce over the mixture, tossing constantly for 1 minute until the sauce thickens and coats everything beautifully.
Transfer to a plate and garnish with sesame seeds before serving.