How to Make It
In a medium bowl, combine the garlic, ginger, 1 tablespoon of the olive oil, cumin, coriander, 1/2 teaspoon of salt and 1/4 teaspoon of black pepper. Add the flank steak and stir to coat. Refrigerate for 1 hour.
Meanwhile, preheat the oven to 450°. Cut the potatoes lengthwise into 1/3-inch-thick-by-1/3-inch-wide sticks. In a large bowl, toss with 3 tablespoons of olive oil, 1/2 teaspoon of salt and 1/4 teaspoon of black pepper. Spread the sticks in one layer on a large baking sheet.
Roast for 20 minutes, then turn the potatoes and spread them out again in one layer. Bake, turning them once or twice more, until the potato sticks are crisp and golden brown, 20 to 25 minutes. Remove from the oven and set aside.
In a measuring cup, stir together the soy sauce, vinegar, oyster sauce and chile paste.
Heat the remaining 1 tablespoon of olive oil in a wok over moderately high heat. Add the marinated flank steak and cook, stirring occasionally, until browned and almost cooked through, about 5 minutes. Add the tomatoes, pickled jalapeños and soy sauce mixture and bring to a boil, then reduce the heat and simmer until the meat is cooked through and the tomatoes are beginning to collapse.
To serve, divide the roasted potatoes among four plates or shallow bowls, and top with the lomo saltado and its sauce. Garnish with cilantro leaves and serve immediately.