For dough, combine masa harina and water. Let stand, covered, for 30 minutes. Meanwhile, in another bowl, beat lard and salt until mixture resembles beaten egg whites (about 6 minutes). Add masa harina mixture 2 tablespoons at a time, beating constantly.
For filling, cook pork and onion, crumbling meat, in a large skillet over medium heat until meat is no longer pink. Add garlic; cook 1 minute longer. Drain. Add next 10 ingredients. Bring to a boil. Reduce heat; simmer, covered, 25 minutes. Cool slightly.
Drain corn husks and pat dry; tear 7-8 husks to make 36 strips for tying tamales. (To prevent husks from drying out, cover with plastic wrap and a damp towel until ready to use.) On wide end of each remaining husk, spread 2-3 tablespoons dough to within 1/2 in. of side edges; top each with 1-2 tablespoons filling. Fold long sides of husk over filling, overlapping slightly. Fold over narrow end of husk; tie with a strip of husk to secure.
Place a large steamer basket in a 6-qt. stockpot over broth; place tamales upright in steamer. Bring to a boil; steam, covered, adding hot water as needed, until dough peels away from husk, about 45 minutes.