To make the marinade, toast the chile on a small skillet over medium heat for less than a minute per side, until toasted but not burnt. In a blender or food processor, puree the chile with the garlic, Worcestershire sauce, Maggi sauce and lime juice. Divide marinade, reserving 1/4 cup for the onions and the rest for the steak.
Place the steak in a zip-lock bag or shallow dish and pour all but 1/4 cup marinade over it to coat. Cover (if in a dish) and refrigerate for at least 2 hours and up to overnight, turning the meat once.
Remove the steak from the marinade. Place in an oven-proof dish and broil for 3 minutes per side. Alternatively, you can grill it for the same amount of time over medium-high heat. You want to cook the meat to somewhere between rare and medium rare. Set aside to rest for 5 to 10 minutes, then slice and cut into 1 to 2-inch pieces, across the grain.
Place the spring onions or scallions in a medium bowl with remaining 1/4 cup marinade.
Preheat the oven to 425 degrees. On a lightly floured surface, stretch dough into a 10 to 12-inch circle and place on a pizza stone or in a cast-iron pan. Bake for 10 minutes. Remove from the oven and spead on 1/2 cup of the pizza sauce leaving a 1/2-inch border all the way around. Top with 3/4 cup mozzarella cheese, place the meat and onions (without their marinade) all over. Reserve the onion marinade for people to add as extra sauce once the pizza is done. Add the remaining mozzarella cheese. Transfer back to the oven and bake until cheese is melted and crust is crisp, about 12 to 14 more minutes.
Transfer to a cutting board and serve the pizza topped with sliced avocado, cilantro leaves, sliced scallions and lime wedges. Drizzle on some reserved onion marinade, too.