Thinly slice the flank steak against the grain into bite-sized strips.
Heat the avocado 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 transfer to a plate.
Reduce heat slightly and add the toasted sesame oil, broccoli florets, and sugar snap peas to the pan.
Stir-fry the vegetables for 3 to 4 minutes until they are bright green and tender-crisp.
Add the minced garlic and fresh ginger, sautéing for 30 seconds until fragrant.
Whisk the coconut aminos into the pan and return the beef along with any juices from the plate.
Toss everything together for 1 minute to glaze the beef and vegetables.
Season with sea salt and black pepper, then garnish with sesame seeds before serving.