Step 1

Trim excess fat and silver skin from 2 lb. skirt or flank steak. Cut meat into 3–4 pieces for skirt steak or 2 pieces for flank steak; transfer to a rimmed baking sheet.

Step 2

Mix 2 Tbsp. Diamond Crystal or 1 Tbsp. plus ½ tsp. Morton kosher salt, 2 Tbsp. light or dark brown sugar, 2 tsp. chipotle chile powder, 2 tsp. freshly ground pepper, 2 tsp. garlic powder, and 2 tsp. ground cumin in a small bowl to combine. Sprinkle rub all over meat, patting to adhere. Chill, uncovered, at least 1 hour and (preferably) up to 4 hours.

Step 3

Prepare a grill for high heat; oil grate. Mix 2 garlic cloves, finely chopped, ¼ cup finely chopped cilantro, 3 Tbsp. fresh lime juice, 2 Tbsp. extra-virgin olive oil, 1 Tbsp. apple cider vinegar, and remaining ¼ tsp. Diamond Crystal or Morton kosher salt in a small bowl to combine. Set dressing aside.

Step 4

Rub steak all over with 3 Tbsp. vegetable oil and grill, turning every 2 minutes or so, until medium-rare (an instant-read thermometer inserted into the center should register 130°), 5–9 minutes (skirt steak is generally thinner and will have a shorter cook time; flank steak is thicker and will take longer). Transfer to a cutting board and immediately brush on all sides with reserved dressing. Let rest 10–15 minutes.

Step 5

If pieces are very wide, cut steak with the grain in half lengthwise. Thinly slice meat against the grain. Arrange on a rimmed platter and drizzle juices from cutting board and any remaining dressing over. Sprinkle with flaky sea salt.