Pat the flank steak dry and slice against the grain into very thin strips.
In a small glass bowl, whisk together the coconut aminos, toasted sesame oil, grated fresh ginger, and minced garlic.
Heat the avocado oil in a large stainless steel skillet or wok over high heat until it begins to shimmer.
Add the beef strips in a single layer, season with sea salt and black pepper, and sear for 2 minutes until deeply browned.
Remove the beef from the pan and set it aside on a plate; add the broccoli florets, sliced bell pepper, and sugar snap peas to the hot skillet.
Stir-fry the vegetables for 3 to 4 minutes until they are tender-crisp and bright in color.
Return the beef and any accumulated juices to the pan, pour the ginger-sesame sauce over the top, and toss for 1 minute to glaze everything.
Transfer to a bowl and garnish with sesame seeds before serving hot.