Heat 1 tablespoon (15 mL) olive oil in a large wok over medium-high heat. Add cauliflower rice. Season with sea salt and black pepper, if desired. Saute for 3-5 minutes, until cooked through.
Remove the cauliflower rice from heat, set aside, and cover to keep warm.
In a small bowl, whisk together the soy sauce, beef broth, sesame oil, ground ginger, and red pepper flakes. Set the sauce aside.
Turn heat back to medium-high. Add another tablespoon (15 mL) olive oil to the wok. Add the ground beef and season with sea salt. Cook for about 8-10 minutes, breaking up with a spatula and stirring occasionally, until browned.
Make a well in the beef and add the minced garlic. Saute for about a minute, until fragrant, then mix into the beef.
Pour the sauce over the beef. Bring to a simmer, then reduce heat and simmer for 3-4 minutes, until the sauce is reduced and thickened. There won't be much liquid left.
Divide the cauliflower rice among plates. Top with ground beef. Garnish with sliced green onions, sesame seeds, and cucumber slices.