Preheat your grill or grill pan over medium-high heat.
In a small bowl, mix olive oil, garlic powder, onion powder, salt, and pepper. Rub this mixture over the flank steak.
Grill the steak for about 5-7 minutes on each side, or until it reaches your desired doneness. Remove from the grill and let it rest for 5 minutes.
While the steak is resting, prepare the salad. In a large bowl, combine the chopped romaine, cherry tomatoes, cucumber, bell pepper, red onion, and avocado.
Slice the grilled steak against the grain into thin strips and add it to the salad.
If using, sprinkle blue cheese crumbles over the top and drizzle with balsamic vinaigrette. Toss gently to combine.
Serve immediately and enjoy!