Slice the flank steak into very thin strips against the grain to ensure a tender, melt-in-your-mouth texture.
In a medium bowl, whisk together the coconut aminos, toasted sesame oil, raw honey, minced garlic, and grated ginger for the marinade.
Add the beef to the marinade, tossing to coat evenly, and let it sit for 10 minutes to absorb the flavors.
Heat a large skillet over medium-high heat and sear the beef in a single layer until deeply browned and caramelized.
In a separate pan, lightly steam the fresh spinach with a tablespoon of water until just wilted, then drain any excess liquid.
Assemble the bowls by layering the warm brown rice, the seared beef, and the prepared spinach, carrots, and cucumber.
Garnish with sliced green onions and sesame seeds for a fresh, aromatic finish.