In a gallon-size Ziploc bag, combine the marinade ingredients and squish to mix well. Trim the flank steak and place it in the bag to marinate in the refrigerator for 1 to 6 hours.

Preheat the oven to 425 degrees. Line a half sheet pan with parchment paper or spray it with nonstick spray. Add the chopped sweet potatoes, drizzle with extra virgin olive oil, and season with garlic salt and pepper. Toss to coat, then spread the potatoes in an even layer and roast for 25-30 minutes, stirring halfway through, until they are golden brown and tender.

Heat an 11" or 12" cast iron grill pan over medium-high to high heat until it starts to smoke, about 5-7 minutes. Remove the steak from the marinade and pat it dry with paper towels. If the steak is too large for the pan, cut it in half and grill in batches.

Place the steak in the hot grill pan and cook until browned char marks appear on the bottom, about 4-6 minutes. Flip the steak and grill for another 4-8 minutes, or until the internal temperature reaches your desired doneness, as measured by a digital meat thermometer.

Transfer the steak to a rimmed quarter sheet pan or a cutting board and let it rest for at least 10 minutes. After resting, slice the steak against the grain.

In a small food processor or blender, combine all ingredients except for the water and pulse until roughly chopped. Add 2 tablespoons of water and process until smooth, adding up to 2 more tablespoons of water to achieve a smooth but not runny consistency. Adjust seasoning with salt, pepper, or lime juice as needed.

To serve, scoop rice into bowls and top with sliced steak, roasted sweet potatoes, sliced avocado, and baby arugula or spinach. Drizzle with the avocado-cilantro sauce and enjoy.