Slice the flank steak against the grain into thin strips and season evenly with sea salt and black pepper.
In a small bowl, whisk together the tamari, grated fresh ginger, minced garlic, and arrowroot powder to create the stir-fry glaze.
Heat the toasted sesame oil in a large skillet or wok over medium-high heat until shimmering.
Add the beef strips to the hot pan in a single layer and sear for 2-3 minutes until browned and caramelized, then remove the beef and set aside.
In the same pan, add the broccoli florets, sliced red bell pepper, and sugar snap peas, sautéing for 4-5 minutes until bright and crisp-tender.
Return the beef to the pan and pour the prepared glaze over the mixture, tossing constantly for 1 minute until the sauce thickens and becomes glossy.
Steam the cauliflower rice in a separate pan or microwave until tender, then serve the beef and vegetable stir-fry over the top.