Cut the pork tenderloin crosswise into 1/2-inch-thick slices. Sprinkle with the salt and white pepper. Lightly flatten the pork by pressing down with your knife or hand and dust with 2 tablespoons cornstarch.
Combine the vinegar, chicken broth and sugar in a small saucepan. Bring to boiling over high heat. Stir in the Thai chiles and garlic. Combine remaining 2 tablespoons cornstarch and 2 tablespoons water in small bowl. Stir into vinegar mixture; cook, stirring occasionally, until thickened, about 2 minutes. Stir in the ketchup and soy sauce. Set aside.
Heat a heavy nonstick skillet or wok over high heat. Add the vegetable oil; heat. Add pork and pan-fry both sides of the pork until brown, about 2 minutes on each side. Add the sauce and cook about 1 minute.
Arrange the pork in 2 rows on a platter, overlapping each piece slightly. Garnish with the tomato slices around the edge of the platter and place the cilantro leaves in the center. Makes 4 servings.