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 garlic, grated fresh ginger, and water to create the stir-fry sauce.
Heat a large skillet or wok over medium-high heat and add the toasted sesame oil.
Add the beef strips to the hot skillet in a single layer and sear for 2-3 minutes until browned, then remove the beef and set aside.
In the same skillet, add the broccoli florets and sliced red bell pepper with a splash of water, covering for 2 minutes to steam-soften.
Remove the lid and sauté the vegetables for another 2 minutes until they are tender-crisp.
Return the beef to the skillet and pour the sauce over the mixture, tossing constantly for 1 minute until the sauce thickens and coats everything evenly.
Garnish with sesame seeds and serve immediately while hot.