Steak and french fries are a classic combination. For their classic dish lomo saltado, Peruvians toss the two together.
In a large bowl, combine the olive oil, cumin, coriander, garlic and a generous pinch each of salt and pepper. Cut the steak into 4-inch pieces; slice the steaks across the grain 1/2 inch thick and add to the bowl along with the onion. Let marinate for 10 minutes.
Meanwhile, in a large skillet, heat 1/2 inch of oil until shimmering. Add the french fries and fry over high heat until golden and crisp, about 3 minutes; drain on paper towels.
Heat a large griddle until very hot. Add the steak and onion along with the pickled jalapeños and stir-fry over high heat until the meat and onion are cooked through and lightly charred, 3 to 4 minutes. Add the tomato and cook until softened and beginning to char, about 1 minute. Add the french fries and cilantro and flip with a spatula to combine. Serve right away with hot sauce.
Very easy and good. My store was out of skirt,so I used flank. The "generous with salt and pepper" really meant be generous! I used 1.5-2 tsp salt.