Heat olive oil in a skillet over medium-high heat.
Add the ground beef, breaking it into small crumbles with a spatula.
Season the beef with sea salt, black pepper, garlic powder, and onion powder.
Cook until the beef is browned and slightly crispy on the edges.
While beef cooks, chop the romaine lettuce, halve the cherry tomatoes, and slice the cucumber and red onion.
In a small bowl, whisk together the yellow mustard and apple cider vinegar to create a simple dressing.
Assemble the bowl by layering the lettuce, tomatoes, cucumber, and onion.
Top with the crispy beef crumbles and sliced avocado.
Drizzle the mustard vinaigrette over the top and serve immediately.