Ancho-and Chipotle-rubbed Pork Loin

• 3 ancho chilies (dried)
• 2 chipotle chilies (dried)
• 2 chipotles in (canned)
• 1 loin of pork (boneless)
• 1 onion (white)
• 14 gr lard
• 6 gr cumin (ground)
• 6 gr salt
• 3 gr garlic (minced)
• 3 gr black pepper (freshly ground)