Heat avocado oil in a skillet over medium-high heat.
Add the ground beef to the skillet, breaking it apart into small crumbles with a spatula.
Season the beef with sea salt, black pepper, and garlic powder; cook until browned and fully cooked through.
While the beef cooks, chop the romaine lettuce, halve the cherry tomatoes, and thinly slice the red onion.
In a small ramekin, whisk together the Greek yogurt and yellow mustard to create a clean special sauce.
Assemble the bowl by placing the romaine lettuce at the base and topping it with the cooked beef, tomatoes, onions, pickles, and sliced avocado.
Drizzle the yogurt-mustard sauce over the top and serve immediately.