Preheat oven to 325°F, turn on the heat to medium in a 4-quart pot add the onion, cook for 1 minute, stirring occasionally, add dry oregano and kosher salt, stir once or twice, add the chicken stock and brown rice, bring back to a boil, cover and reduce heat to medium cook for 10 minutes. Once the rice is finished, add the cilantro, stir to fluff, and steam for 5 minutes.
In a small dish add the lime juice, dip flank in juice making sure both sides are covered. In a small bowl mix the garlic powder, onion powder, kosher salt, black pepper, cumin, and oregano. Liberally season both sides of the flank. Turn on the heat to medium-high in a large skillet spray with cooking spray for 2 seconds, cook flank for 2 minutes on each side. Transfer to a foiled lined baking sheet, pop in the oven for 20 minutes. Remove from the oven and rest for 10 minutes. Slice steak into small to medium strips.
Turn on the heat to medium in the same large skillet you cooked the flank in add avocado oil, onion, bell peppers, kosher salt, black pepper, and garlic powder, cook for 5-8 minutes, stir in the butter.
Serve 4 oz. of flank with 4 oz. cilantro rice and 2 oz. of onions and peppers per serving.