Making real tamales with anything but good, fresh lard is like making duck confit or pork rillettes with, say, vegetable oil. It can certainly be done, but at a flavorful sacrifice. Two-thirds of a cup is used in the base tamale batter.
Reconstitute the corn husks.
In the jar of a blender, combine chiles, garlic, pepper, and cumin. Add 1 1/2 cups water, and blend until a smooth puree forms.
Strain mixture into a medium saucepan. Add the pork, 1 3/4 cups water, and salt. Place over medium heat; cook, stirring frequently, until liquid has reduced to consistency of a thick sauce and meat is very tender, 50 to 60 minutes. Using a fork, break up the meat.
Place the classic tamale batter in a large bowl. Add 3 tablespoons sauce; combine.
Assemble twelve tamales with the batter and the pork filling, using large husks for wrappers and ties, and reserving smaller ones to line basket and cover the tamales.
Prepare the steamer, and steam the tamales. Let stand until batter has firmed. Serve tamales with the salsa.