In a small bowl, whisk together olive oil, minced garlic, ground cumin, chili powder, salt, and pepper. Rub this aromatic mixture generously over the flank steak and let it marinate.

In a medium saucepan, bring water to a boil. Stir in rice and a pinch of salt, cover, and simmer for 18–20 minutes. Fluff with a fork and set aside.

Preheat your grill. Grill the marinated flank steak for 4–5 minutes each side until desired doneness. Let it rest for 5 minutes.

Combine cooked rice, drained black beans, corn, diced tomatoes, chopped red onion, chopped cilantro, and lime juice in a large bowl. Toss gently.

Slice the rested steak against the grain. Divide the rice mixture among bowls and arrange sliced steak on top.

Top the bowls with avocado, cheese, and optional sour cream or salsa for added richness.