In a small bowl, whisk together olive oil, 3 tablespoons lime juice, minced garlic, cumin, salt, and pepper to create the marinade.
Place the flank steak in a sealable bag or shallow dish, pour the marinade over it, and refrigerate for 30 minutes.
Preheat an outdoor grill or indoor grill pan to medium-high heat.
While steak is marinating, prepare the sauce by blending Greek yogurt, cilantro, 1 tablespoon lime juice, and jalapeño in a food processor until smooth.
Grill the flank steak for 5 to 7 minutes per side or until it reaches an internal temperature of 135°F (57°C) for medium-rare.
Remove steak from heat and let it rest for 10 minutes before slicing thinly against the grain.
Divide the cooked rice among four bowls.
Top each bowl with black beans, corn, cherry tomatoes, sliced avocado, and the grilled steak slices.
Drizzle the creamy cilantro lime sauce over each bowl and serve immediately.