Mix olive oil, cumin, chili powder, salt, and pepper in a small bowl. Rub over flank steak and marinate for at least 30 minutes.

Preheat grill or skillet to medium-high heat (about 400°F).

Cook marinated flank steak for 4-5 minutes per side for medium-rare, using a meat thermometer to check for 130°F.

Let the steak rest for about 10 minutes after cooking, then slice against the grain.

Prepare corn and vegetables: grill fresh corn until slightly charred, or sauté frozen/canned corn for about 5 minutes. Chop cherry tomatoes and dice red onion.

Slice avocados in half, remove pits, scoop out flesh, and slice into wedges. Drizzle with lime juice.

Assemble bowls: start with quinoa or brown rice, layer sliced steak, corn, tomatoes, onion, and avocado.

Finish with lime juice and cilantro. Serve with hot sauce or salsa if desired.