Combine first 5 ingredients in a small skillet. Place over medium heat, and cook 3 1/2 minutes or until toasted, stirring constantly. Place spice mixture in a spice or coffee grinder, and process until finely ground. Rub spice mixture over pork; cover and refrigerate 2 hours.
Cut chiles in half lengthwise; discard seeds and membranes. Place chile halves, skin sides up, on a foil-lined baking sheet. Broil 10 minutes or until blackened. Place chiles in a heavy-duty zip-top plastic bag, and seal; let stand 10 minutes. Peel chiles. Chop chiles; set aside.
Place pineapple in a blender, and process until smooth. Remove 1/2 cup pineapple purée from blender, and place in a large bowl; set aside. Add chopped chiles, 2 tablespoons lime juice, and 1/4 teaspoon salt to pineapple purée in blender; process until smooth. Pour into a small nonaluminum skillet; stir in mint.
Add papaya, raisins, green onions, and 2 tablespoons lime juice to 1/2 cup pineapple puree in bowl; stir well. Cover salsa, and chill.
Preheat oven to 400°. Place pork on broiler pan coated with cooking spray; sprinkle piloncillo sugar and 1/4 teaspoon salt over pork. Bake at 400° for 30 minutes or until a meat thermometer registers 160°. Cut pork diagonally across the grain into thin slices; set aside, and keep warm.
Cook pineapple-chile purée mixture over medium heat until thoroughly heated, stirring occasionally; spoon purée onto individual plates. Arrange pork slices over purée, and spoon papaya salsa over pork. Garnish with fresh mint, if desired.