Sprinkle steak with 1/2 teaspoon salt and pepper; rub with the garlic, jalapeño and lime juice. Refrigerate for up to 4 hours.
In a medium bowl, combine masa and 1 teaspoon salt. Add water and knead until mixture comes together. Divide dough evenly into 16 pieces. Using wet hands, press pieces of dough into 3 1/2-inch circles.
Heat a large skillet or comal over medium heat. Add sopes and cook for 6 minutes, turning once, until golden brown. Remove from heat and place in warm oven.
Preheat an outdoor grill or stove top grill pan over medium-high heat. Add steak and cook until well browned, about 5 minutes. Turn and continue cooking until desired doneness is reached.
Transfer steak to cutting board and let rest 5 minutes. Thinly slice steak in strips then dice into 1/2-inch pieces.
Top sopes with steak, black beans, pico de gallo, avocado and queso fresco, dividing evenly. Garnish with cilantro and lime if desired.