Step 1

Pulse cilantro, scallions, chiles, garlic, and 1 tsp. Diamond Crystal or ½ tsp. Morton kosher salt in a food processor (a mini processor works well here) until a coarse paste forms. Transfer to a small heatproof bowl.

Step 2

Heat ⅓ cup oil in a small skillet over medium-high. Cook cumin until fragrant, about 10 seconds. Transfer to bowl with paste; add peanuts and mix well. Set scallion thecha aside for serving.

Step 3

Pat steaks dry with paper towels and season on both sides with kosher salt. Rub a little oil over steaks to coat lightly.

Step 4

Heat a large cast-iron skillet over medium-high. Add half of the steak, arranging in a single layer, and cook, undisturbed, until a golden brown crust forms, 2–3 minutes. Turn steak over and cook until second side forms a golden brown crust, 2–3 minutes. (Steak should be thin enough that once it’s seared it will be cooked to medium-rare—about 125° on an instant-read thermometer. If you have a very hot pan, this will happen quickly.) Transfer steak to a cutting board and repeat process with remaining steak. Let rest 10 minutes.

Step 5

Slice steak against the grain and arrange on a platter. Top with reserved scallion thecha and sprinkle with sea salt.