Slice the flank steak against the grain into thin, bite-sized strips.
Whisk together the coconut aminos, minced ginger, and minced garlic in a small bowl 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 until browned, about 2-3 minutes, then remove and set aside.
In the same pan, add the broccoli florets and sliced red bell pepper with a splash of water, covering for 2 minutes to steam-tenderize.
Return the beef to the pan and pour the sauce over the mixture, tossing constantly until the sauce thickens and coats everything evenly.
Season with sea salt and black pepper, then garnish with sesame seeds before serving warm.