Slice the flank steak against the grain into very thin strips to ensure maximum tenderness.
In a medium bowl, whisk together the coconut aminos, toasted sesame oil, honey, grated ginger, minced garlic, and red pepper flakes.
Add the steak strips to the bowl, tossing well to coat, and marinate for 15 minutes at room temperature.
Heat the avocado oil in a large cast-iron skillet or wok over high heat until it begins to shimmer.
Spread the beef in a single layer and sear without moving for 2 minutes until a dark, caramelized crust forms.
Flip the beef and cook for another 60 seconds, then remove the meat from the pan and set aside.
Add the cauliflower rice to the same hot skillet, seasoning with sea salt and black pepper, and sauté for 3 minutes until tender-crisp.
Divide the cauliflower rice into bowls, top with the sesame beef, and garnish with sliced green onions and sesame seeds.