Grilled Cabbage Cemitas

Name: Grilled Cabbage Cemitas
Ingredients: 1/2 medium green cabbage (1 pound), cut through the core into 1 1/2-inch wedges; 1/2 medium red cabbage (1 pound), cut through the core into 1 1/2-inch wedges; 1/4 cup extra-virgin olive oil, plus more for brushing; 2 large garlic cloves, minced; 1/2 teaspoon cumin seeds; Kosher salt; 4 cemita buns, kaiser rolls or hoagie rolls, split; 1 Hass avocado, halved and pitted; 1 cup shredded fresh mozzarella (4 ounces); 1/2 cup lightly packed cilantro leaves; Hot sauce, for serving