Grilled Chicken with Board Dressing

INGREDIENTS

• 1 dried guajillo or New Mexico chile or 1/2 teaspoon crushed red pepper flakes
• 3/4 chopped fresh cilantro
• 1/4 chopped fresh oregano
• 1 finely grated lime zest
• 1/4 olive oil plus more for grill
• Kosher salt, freshly ground pepper
• 1 4-pound chicken, halved, backbone removed
• Lime wedges (for serving)