Season the flank steak generously with salt and black pepper on both sides.
Heat 1 tablespoon of avocado oil in a heavy cast-iron skillet over medium-high heat until shimmering.
Sear the steak for 4 to 5 minutes per side for medium-rare; remove from heat and let rest for 10 minutes before slicing against the grain.
In the same skillet, add the remaining oil and the corn kernels; cook undisturbed for 3 minutes to char, then stir in smoked paprika and lime juice.
In a high-speed blender, combine Greek yogurt, cilantro, garlic, lime juice, and water; process until completely smooth and bright green.
Divide the cooked grain base into four bowls.
Arrange the sliced steak, roasted corn, black beans, cherry tomatoes, and avocado slices over the grains.
Drizzle the cilantro cream sauce evenly over each bowl and serve immediately.