Preparation

1. Step 1

   Heat the grill to high. In a container that fits the steak, stir together 2 tablespoons Worcestershire and 2 tablespoons oil. Season the steak lightly with salt and generously with pepper, then toss to coat in the marinade. Let sit while you make the tomatoes (or up to 24 hours in the refrigerator).

2. Step 2

   In a medium bowl, stir together the tomatoes, shallot, capers, brine, remaining ½ teaspoon Worcestershire and the remaining 3 tablespoons oil. Season to taste with salt and pepper. Set aside (up to 1 hour ahead).

3. Step 3

   Shake the marinade off the steak. Grill the steak, flipping every 3 minutes, until well-browned and 130 degrees in the thickest part for medium-rare, 6 to 15 minutes, depending on the thickness of the steak. (If using a gas grill, cover grill between flips.) Transfer to a cutting board to rest for at least 5 minutes.

4. Step 4

   Slice the steak and top with the tomatoes and all the juices in the bowl, followed by the chives.