Pat the flank steak dry and season both sides with kosher salt, black pepper, smoked paprika, and garlic powder.
Heat 1 tablespoon of olive oil in a cast-iron skillet over medium-high heat until shimmering.
Place steak in the skillet and sear for 4 to 5 minutes per side for medium-rare; remove from heat and let rest for 10 minutes.
Wipe the skillet clean, add the remaining 1 tablespoon of olive oil, and increase heat to high.
Add corn kernels to the skillet and cook undisturbed for 2-3 minutes until charred, then toss and cook for another 2 minutes.
In a small mixing bowl, whisk together the lime juice and chopped cilantro.
Slice the rested steak against the grain into 0.5-inch thick strips.
Distribute the cooked brown rice into two bowls.
Arrange the sliced steak, roasted corn, and sliced avocado over the rice.
Drizzle the cilantro-lime mixture over each bowl and serve immediately.