Heat a grill pan or griddle to medium-high. Combine the tomato paste, lemon juice, horseradish and Worcestershire in a bowl. Whisk in the EVOO, then the parsley; season with black pepper and Tabasco.
Combine the romaine, endive and celery in a large bowl.
Add the steak to the grill pan, season with salt and pepper and cook, turning occasionally, until the center is pink, 12 to 15 minutes. Let the meat rest, loosely covered with foil, for about 10 minutes, then slice across the grain.
Toss the salad with half of the dressing. Serve the sliced steak on the top and drizzle with the remaining dressing. Sprinkle with the caperberries or olives.