Cut the pork into large chunks about 3 inches across. Put them into a large, lidded pot and cover with water by 1 inch. Bring to a boil and skim any froth off. Lower the heat to a simmer and add 1/4 of the onion, 2 garlic cloves and the bay leaves. Salt to taste and cook until the pork is tender.
Remove the seeds and stems of all the chiles. It's OK if a few seeds get stuck.
Meanwhile, make the salsa. Heat a comal or griddle or heavy frying pan over high heat and char the rest of the onion and the garlic cloves.
While the vegetables are charring, bring a medium pot of water to a boil. While that is heating, quickly toast the chiles on the hot comal -- about 30 seconds total, flipping a couple times. You want the dried chiles to blister a little, but not blacken. When they are toasted and the pot of water hits a boil, put the chiles in the water and turn off the heat.
If you want, toast the cumin and coriander seeds in a hot, dry pan until they smell nice. Put them in a spice grinder or a blender and grind. This step does add a lot of flavor.
When the onions and garlic are nicely charred and the chiles soft, put them in a blender with the oregano and spices, salt, vinegar and enough water to make a sauce with the consistency of cream. Puree.
Once the pork is tender, drain the broth and discard it or use in another recipe. Wipe out the pot and add the lard. When it's hot, add the chunks of pork and sear hard on one side -- you want a combination of crispy and soft.
When you have achieved that, pour in the salsa and mix well. Turn the heat to a simmer and cook for 10 to 20 minutes, then serve.
The timing reflects farmed pork or a young wild hog. Older animals might take longer to get tender.
Keys to Success
Pork shoulder is preferred, but really any cut of pork will work. And as I mentioned, you can use chicken thighs, upland game birds, rabbits or even venison if you wanted to.
The chile mix determines the heat level. Skip the chipotles if you want to keep it mild, and for a redder sauce, use only guajillos, or New Mexican red chiles or California chiles, which are dried red Anaheims.
If you hate vinegar, use lots of lime juice.
Hate lard? Use some other oil.
Once made, you can keep this for a week in the fridge, and it freezes well.