In a medium bowl, whisk together fresh lime juice, olive oil, chopped cilantro, minced garlic, ground cumin, chili powder, salt, and black pepper until well combined. Place the flank steak into the marinade, ensuring it is fully coated. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes; for optimum flavor, marinate for 2 to 4 hours.

While the steak marinates, cook 1 cup of rice according to package instructions, using water or broth for added flavor. In a small saucepan, pour in 1 can of rinsed and drained black beans and heat over medium heat for about 5 minutes, stirring occasionally. If desired, season the beans with a pinch of salt or cumin for extra flavor.

For the corn, you can either boil or sauté it. If using fresh corn, cut the kernels off the cob and sauté them in a pan over medium heat for about 5 minutes until tender. Alternatively, heat 1 cup of frozen corn until warmed through, about 3-4 minutes in a saucepan. Set aside once cooked.

Preheat your grill or grill pan to medium-high heat, about 400°F (200°C). Remove the flank steak from the marinade and discard the excess marinade. Grill the steak on each side for 4-5 minutes or until it reaches a medium-rare doneness at 130°F. Once finished, transfer the steak to a cutting board and let it rest for 5 minutes before slicing thinly against the grain.

To build your Cilantro Lime Steak Bowls, start by dividing the cooked rice among serving bowls. Top each with the seasoned black beans, sautéed corn, halved cherry tomatoes, sliced avocado, and chopped red onion. Layer the thinly sliced steak on top, and if desired, sprinkle with crumbled feta cheese. Finish by garnishing with extra cilantro and lime wedges for serving.