In a medium bowl, whisk together lime juice, olive oil, cilantro, garlic, cumin, chili powder, salt, and black pepper.

Add the flank steak to the bowl and coat it well with the marinade.

Cover and refrigerate for at least 30 minutes, preferably 2-4 hours.

Cook rice according to package directions until tender.

In a small saucepan, heat black beans over medium heat for about 5 minutes.

If using fresh corn, boil or sauté briefly until tender. If using frozen corn, heat it as needed.

Preheat your grill or grill pan to medium-high heat.

Remove the steak from the marinade, letting any excess marinade drip off before discarding it.

Grill the steak for 4-5 minutes on each side for medium-rare or to desired doneness.

Let the steak rest for 5-10 minutes before slicing it thinly against the grain.

Divide the cooked rice into bowls as the base.

Add black beans, corn, cherry tomatoes, avocado slices, and red onion on top.

Place sliced steak over the veggies and top with feta cheese if desired.

Garnish with extra cilantro and serve with lime wedges.