In a mixing bowl, combine the olive oil, cumin, salt, and lime juice. Whisk together until well blended. Add the flank or skirt steak to the bowl, ensuring it is thoroughly coated with the marinade. Cover and let it marinate for at least 30 minutes, or up to 2 hours for maximum flavor.
Preheat your grill or skillet over medium-high heat. If using a grill, ensure the grates are clean and lightly oiled to prevent sticking.
Remove the steak from the marinade and place it on the hot grill or skillet. Cook for about 5-7 minutes on each side for medium-rare, or until it reaches your desired doneness. Once cooked, transfer the steak to a cutting board and let it rest for a few minutes.
Using a sharp knife, slice the steak against the grain into thin strips. This will ensure that each bite is tender and easy to chew.
Slice the rolls in half and lightly toast them on the grill or in a toaster. On the bottom half of each roll, layer the sliced steak, a generous spoonful of the RO*TEL diced tomatoes, and a handful of fresh cilantro. Add any additional toppings you desire, such as avocado, jalapeños, or sliced onions.
Close the sandwich with the top half of the roll, slice in half if desired, and serve immediately. Enjoy your homemade Torta Recipe (Mexican Steak Sandwich) with a side of chips or a fresh salad!