Thinly slice the flank steak against the grain into bite-sized strips and season with sea salt and black pepper.
In a small bowl, whisk together the coconut aminos, minced fresh ginger, minced garlic, arrowroot powder, and water to create the stir-fry sauce.
Heat the toasted sesame oil in a large skillet or wok over medium-high heat until shimmering.
Add the beef strips to the pan in a single layer and sear for 2-3 minutes until browned and caramelized, then remove and set aside.
Add the broccoli florets to the same pan with a splash of water, covering for 2 minutes to lightly steam until they reach a vibrant green.
Return the beef to the pan and pour the sauce over the mixture, tossing constantly for 1 minute until the glaze thickens and coats everything evenly.
Transfer to a plate and garnish with sesame seeds before serving hot.