Heat a large skillet over medium-high heat. Saute steak in hot skillet until browned on the outside and cooked through, about 5 minutes. Season with salt and pepper. Remove to a plate and keep warm.
Heat oil in the same skillet. Place a tortilla in the hot oil and cook, turning once, until tortilla is lightly browned and flexible. Repeat with remaining tortillas.
Place tortillas on a plate and top each with steak, onion, jalapeno, and cilantro. Squeeze lime juice over the top.
