Eggplant Marinara Sandwiches

Name: Eggplant Marinara Sandwiches
Ingredients: 1 medium-large eggplant (about 1 pound), cut into 1/2-inch-thick rounds (12 to 14); Kosher salt and freshly ground pepper; 5 tablespoons extra-virgin olive oil, plus more for the grill pan; 4 cloves garlic, thinly sliced; 1 15-ounce can cherry tomatoes; 1/2 teaspoon red pepper flakes; 4 cups baby arugula; Juice of 1/2 lemon; 4 ciabatta rolls, split and toasted; 1 8-ounce ball fresh mozzarella cheese, halved and thinly sliced; Grated pecorino romano cheese, for sprinkling; 1/2 cup fresh mint