Prepare the brown rice according to package directions and set aside.
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, rice vinegar, grated fresh ginger, and minced garlic 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 hot skillet in a single layer and sear until browned, about 2 minutes; remove the beef from the pan and set aside on a plate.
Add the broccoli florets to the same skillet with a tablespoon of water, then cover and steam for 3 minutes until vibrant green and tender-crisp.
Return the beef to the skillet and pour the prepared sauce over the mixture, tossing constantly for 1 minute until the glaze thickens and coats the ingredients.
Serve the beef and broccoli over the warm brown rice and garnish with sesame seeds before serving.