In a small bowl, toss the sliced cucumber with rice vinegar and sea salt; set aside to quick-pickle.
Heat a large skillet over medium-high heat with half of the toasted sesame oil.
Add the ground beef, grated ginger, and minced garlic to the skillet, breaking the meat up until browned and cooked through.
Stir in the coconut aminos and black pepper, allowing the sauce to glaze the beef for 2 minutes.
Remove the beef from the pan and quickly sauté the spinach and shredded carrots until just wilted.
In the same pan, lightly toast the cauliflower rice and cooked brown rice together until heated through.
Wipe the pan and fry the egg until the whites are set but the yolk remains runny.
Assemble the bowl by layering the rice mixture, topped with the bulgogi beef, sautéed veggies, pickled cucumbers, and the fried egg.
Garnish with sesame seeds and the remaining drizzle of toasted sesame oil.