Pat the sirloin steak and shrimp dry with paper towels and season both with sea salt and black pepper.
Heat a large cast-iron skillet or wok over medium-high heat and add half of the ghee.
Add the steak cubes in a single layer, searing for 2-3 minutes until browned and caramelized, then remove and set aside.
Add the remaining ghee to the skillet and sear the shrimp for 1-2 minutes per side until pink and opaque; remove and set aside with the steak.
Toss the sliced zucchini, onions, and mushrooms into the hot pan, sautéing for 4-5 minutes until the vegetables are tender-crisp.
Stir in the minced garlic, grated ginger, coconut aminos, and toasted sesame oil, cooking for 1 minute until fragrant.
Return the steak and shrimp to the pan, tossing everything together quickly to coat in the savory sauce.
Garnish the dish with sesame seeds and serve immediately while hot.