If marinating the steak, place it in a casserole dish. Pour the Steak Marinade over the steak and turn to coat completely. Cover and refrigerate for a few hours or overnight.
When ready to cook, remove the steak from the marinade, if using, and allow the steak to come to room temperature. Discard the marinade. Preheat a grill pan or outdoor grill to high. Season the steak with salt and black pepper. Grill the steak to the desired doneness, 10 to 15 minutes for medium rare (an instant-read thermometer inserted into the thickest part of the steak should register 130 degrees F). Place the steak on a cutting board and allow to rest at least 5 minutes.
Meanwhile, place the bell peppers on the grill. Turn the peppers frequently, charring the skin evenly on all sides, 5 to 8 minutes. Transfer the peppers to a large bowl. While the peppers are still piping hot, cover the bowl tightly with plastic wrap and allow the peppers to steam for 15 minutes. Place the peppers on a cutting board. Remove the stems and seeds. Using a kitchen towel, wipe off the charred skin. Slice the peppers into strips. Place the pepper strips in a medium bowl and drizzle with oil. Set aside.
Slice the zucchini lengthwise into 3/4-inch-thick planks. Place in a large bowl, drizzle with oil, season with salt and black pepper and toss to coat. Grill the zucchini until tender, 2 to 3 minutes per side. Set aside.
Drizzle a little oil on the cut sides of the ciabatta and toast on the grill.
In a medium bowl, combine the goat cheese and cream and whisk together until smooth. Set aside.
For the chile salsa verde: Combine the chiles, garlic, onions, parsley, oregano, cilantro and oil in a large bowl and mix well. Season with salt. Set aside.
To assemble the sandwiches, thinly slice the steak against the grain. Place a dollop of the whipped goat cheese on both halves of the toasted ciabatta and spread evenly. Layer the sliced steak over the cheese and put a generous amount of the chile salsa verde on top of the steak. Layer the grilled zucchini and roasted peppers into the sandwiches. Close the sandwiches with the top half of ciabatta, slice and serve.
Steak Marinade (optional):
Combine the Worcestershire, oil, garlic, rosemary and chile in a large bowl and mix well.