Slice the flank steak against the grain into very thin strips and season with sea salt and black pepper.
In a small bowl, whisk together the coconut aminos, water, minced ginger, and arrowroot powder to create the stir-fry sauce.
Heat the toasted sesame oil in a large skillet or wok over medium-high heat.
Add the beef strips to the hot skillet in a single layer and sear until browned, about 2 minutes, then remove beef and set aside.
Add the broccoli florets and minced garlic to the same skillet with a splash of water, covering for 2 minutes to steam until tender-crisp.
Return the beef to the skillet and pour the sauce mixture over the ingredients.
Toss everything together for 1-2 minutes until the sauce thickens and coats the beef and broccoli beautifully.
Steam the cauliflower rice in a separate pan or microwave until tender.
Serve the beef and broccoli over the cauliflower rice and garnish with sesame seeds.