Heat a non-stick skillet over medium-high heat.
Add the ground beef to the hot skillet, breaking it apart into small crumbles with a spatula.
Season the beef with sea salt, black pepper, and garlic powder.
Cook the beef undisturbed for 3-4 minutes to develop a crispy crust, then stir and cook until fully browned.
While the beef is browning, finely shred the romaine lettuce and finely dice the white onion and dill pickles.
In a small mixing bowl, whisk together the Greek yogurt, yellow mustard, unsweetened ketchup, and pickle juice until the sauce is smooth and creamy.
Place the shredded romaine lettuce in a large serving bowl as the base.
Top the lettuce with the warm, crispy ground beef, followed by the diced onions and pickles.
Sprinkle the shredded cheddar cheese and sesame seeds over the beef.
Drizzle the prepared special sauce over the entire bowl and serve immediately.