Steak-and-Avocado Sandwich

skirt steak, cut crosswise into 4 pieces

Kosher salt and freshly ground pepper

extra-virgin olive oil

Worcestershire sauce

medium red onion, chopped (1 1/2 cups)

black beans, undrained

Sliced tomato and avocado, Mexican crema or sour cream, and hot sauce, for serving

hoagie rolls (preferably seeded), split, for serving