Thinly slice the flank steak against the grain into bite-sized strips and season with sea salt and black pepper.
Mince the fresh ginger and garlic, and slice the red bell pepper into thin strips.
Heat the toasted sesame oil in a large skillet or wok over medium-high heat until shimmering.
Add the beef strips to the pan in a single layer and sear for 2 minutes until browned, then remove beef from the pan and set aside.
In the same pan, add the broccoli florets, bell pepper, and snap peas, sautéing for 3-4 minutes until tender-crisp.
Stir in the minced ginger and garlic, cooking for 30 seconds until fragrant.
Return the beef to the pan and pour in the coconut aminos, tossing everything together for 1 minute to coat and glaze.
Remove from heat and garnish with sesame seeds before serving immediately.