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, grated fresh ginger, and red pepper flakes to create the stir-fry sauce.
Heat a large skillet or wok over medium-high heat and add the toasted sesame oil.
Add the broccoli florets to the pan with a splash of water, covering for 2 minutes to steam until they are bright green and tender-crisp.
Remove the broccoli from the pan and set aside; increase the heat to high.
Add the steak strips to the hot pan in a single layer, searing for 1-2 minutes per side until beautifully browned.
Add the minced garlic and cook for 30 seconds until fragrant, then return the broccoli to the pan.
Pour the sauce over the beef and broccoli, tossing constantly for 1 minute until the glaze thickens and coats everything.
Garnish with sesame seeds before serving hot.