Slice the flank steak against the grain into very thin strips and season evenly with sea salt and black pepper.
In a small glass bowl, whisk together the coconut aminos, minced ginger, minced garlic, toasted sesame oil, and arrowroot powder until smooth.
Heat the avocado oil in a large stainless steel skillet or wok over medium-high heat until it begins to shimmer.
Add the beef strips in a single layer and sear for approximately 2 minutes until browned and caramelized, then remove the beef from the pan and set aside.
Add the broccoli florets to the same pan with two tablespoons of water, covering with a lid for 2-3 minutes to steam until they are tender-crisp and bright green.
Return the seared beef to the pan and pour the prepared sauce over the mixture, tossing constantly for 1 minute until the sauce thickens into a glossy glaze.
In a separate small non-stick skillet, sauté the cauliflower rice over medium heat for 3-4 minutes until softened and hot.
Plate the cauliflower rice and top with the sesame beef and broccoli, finishing the dish with a sprinkle of sesame seeds.