Pork Kebabs al Pastor

Name: Pork Kebabs al Pastor
Ingredients: 3 dried chiles de árbol, wiped clean; 1 cup chopped fresh pineapple; 1/2 cup distilled white vinegar; 2 tablespoons vegetable oil; 2 large garlic cloves, smashed; 1 teaspoon dried oregano; 1/2 teaspoon ground cumin; 1 pound tomatoes (4 medium), halved; 1 small white onion (6 to 8 ounces), quartered; 3 tablespoons water; 1/4 cup chopped cilantro; 2 pounds boneless pork shoulder, cut into 1 1/2-inch chunks; 1 large white onion, cut into 1 1/2-inch pieces; 3 cups (1-inch) chunks fresh pineapple; 16 (6-inch) corn tortillas; Equipment: 12 (12-inch) wooden skewers, soaked in water 30 minutes; Accompaniments: fresh cilantro; lime wedges; thinly sliced radishes