Pibil-Style Pork

INGREDIENTS

• 1 4 1/2- to 5-pound bone-in pork shoulder roast (Boston butt)
• 1/3 cup fresh orange juice
• 1 tablespoon red wine vinegar
• 1 teaspoon ground black pepper
• 1/4 cup achiote paste
• 1 medium onion, quartered through core
• Corn tortillas
• 4 garlic cloves, peeled
• 1 teaspoon ground cumin
• 1/3 cup fresh lime juice
• 1/2 teaspoon dried oregano (preferably Mexican)
• 2 teaspoons coarse kosher salt