Begin by heating up your grill or a large cast iron skillet or griddle to medium-high heat. You want the pan or grill very hot before putting the meat on. Heat for 5 minutes.
Meanwhile, remove flank steak from packaging and rub olive oil on each side. Then season generously on each side with chile lime seasoning and garlic salt. If you can't find Chile Lime seasoning (I get mine at Trader Joe's), you can easily season with chili powder and a squeeze of fresh lime juice.
Once seasoned, use tongs to transfer steak to heated pan or grill. Sear/cook on each side for 4-7 minutes until cooked to your liking (we like ours medium - medium well).
Once steak is cooked to your liking, remove from pan or grill and let rest on a cutting board for 10 minutes. Sprinkle with additional garlic salt.