Simple Cauliflower Tacos

Name: Simple Cauliflower Tacos
Cook time: 40 min
Total time: 40 min
Cuisine: American, Mexican, Latin American, TexMex
Ingredients: 2 tablespoons red wine vinegar; 1 1/2 tablespoons cold water; 1/4 teaspoon granulated sugar; Kosher salt; 1/2 red onion, thinly sliced; 3 tablespoons olive oil; 1 large (3 pounds) head cauliflower, trimmed, chopped small, including core; Red pepper flakes; 1 heaped teaspoon ground cumin; 1 lime, halved; 1 15-ounce can black beans, drained and rinsed; 12 small (4 to 5-inch) or 8 medium (7-inch) corn or flour tortillas; 1/2 to 1 avocado, thinly sliced (to taste); 1/2 cup crumbled cotija cheese; Chopped fresh cilantro; Hot sauce and/or pickled jalapeños