In a mixing 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 in a shallow dish, pouring the marinade over it to coat evenly. Cover it with plastic wrap and refrigerate for at least 30 minutes, or up to 4 hours for maximum flavor infusion.

While the steak is marinating, cook your rice according to package instructions, typically simmering in water for 18-20 minutes until fluffy. In a small saucepan, heat black beans over medium heat for about 5 minutes until warmed through, stirring occasionally. Season them to taste with salt and a sprinkle of cumin for added flavor.

If using fresh corn, remove the kernels from the cob and either boil them in salted water for 3-5 minutes or sauté them in a pan with a little olive oil. For frozen corn, cook according to package directions, usually about 2-3 minutes in a skillet over medium heat until heated through. Set aside once ready.

Preheat your grill or grill pan to medium-high heat. Remove the marinated flank steak from the refrigerator, letting excess marinade drip off. Grill the steak for about 4-5 minutes per side, cooking until it reaches an internal temperature of 130°F for medium-rare. Once done, let it rest for 5-10 minutes to retain its juices, then slice against the grain into thin strips.

Start by dividing the fluffy rice among serving bowls as the base. Layer on the warmed black beans and corn, followed by chopped cherry tomatoes, diced avocado, and sliced red onion. Finally, top each bowl with the sliced grilled steak and, if desired, crumbled feta for a creamy contrast. Garnish with extra cilantro and serve with lime wedges for an extra zesty kick.