In a small bowl, whisk together the Greek yogurt, yellow mustard, and finely chopped dill pickles to create the creamy special sauce.
Heat the olive oil in a skillet over medium-high heat and add the diced white onion, sautéing for 2-3 minutes until translucent.
Add the ground beef to the skillet, breaking it up with a spatula, and season with sea salt, black pepper, garlic powder, and smoked paprika.
Cook the beef until fully browned and slightly crispy on the edges, then remove from heat.
Place the shredded romaine lettuce in a large bowl as the base.
Top the lettuce with the cooked beef mixture, shredded cheddar cheese, and sliced avocado.
Drizzle the prepared creamy sauce over the bowl and serve immediately.