Slice dried chiles in half lengthwise.

Remove and discard stems and seeds.

Place chiles in a bowl, and add boiling water to cover.

Let stand 20 minutes or until chiles are softened.

Drain chiles, reserving liquid.

Cook cumin seeds in a skillet over medium heat 30 seconds.

Add oregano, and cook, stirring constantly, 30 seconds or until cumin is toasted.

Process cumin mixture, soaked chiles, 1 cup reserved liquid, garlic, and next 4 ingredients in a blender or food processor until smooth, adding more reserved liquid if needed.

Place pork in a shallow dish.

Pour half of chile mixture over meat.

Cover and chill 30 minutes.

Remove pork from marinade, discarding marinade.

Grill pork, covered with grill lid, over medium-high heat (350° to 400°), turning occasionally and basting with reserved chile mixture, 20 minutes or until a meat thermometer inserted into thickest portion registers 155°.

Remove from grill; let stand 10 minutes until pork reaches 160°.

Coarsely chop pork.