1. Preheat the oven to 350 degrees.

2. Cut the pork into 6 or 8 pieces. Melt the lard in a heavy Dutch oven just large enough to hold the meat in one layer. Brown the meat on all sides and season with salt.

3. Squeeze the orange over the meat and toss the rind into the pan. Pour the milk over the meat and add enough water to almost cover the meat. Sprinkle with pepper. Cover tightly with aluminum foil and bake for about 2 hours, until the meat is fork-tender.

4. To finish, uncover the meat and break into largish pieces. Remove the orange rind and discard. Roast, uncovered, until most of the liquid has evaporated, about 20 minutes, or until the meat is brown and crisp on the edges.

5. To assemble the tacos, fill a warm tortilla with shredded pork. Top with avocado and salsa, a little of the chicharrón, and finish with generous amounts of onion and cilantro.

For the Avocado Cilantro Sauce:

Combine all the ingredients in a blender, using the smaller amount of water. Puree until smooth and all more water, if needed, to make an easily spreadable consistency. Taste for salt and lime, but do not overseason; this sauce should be on the bland side. I keeps, refrigerated, for 24 hours.

For the Raw Tomatillo Salsa:

1. Wash the tomatillos well with warm water to remove the naturally sticky coating, which is bitter. Cut them into quarters.

2. Pulse the tomatillos in a food processor with the remaining ingredients until a slightly chunky texture is achieved.

3. Taste for salt and serve as soon as possible to enjoy maximum bite and crunch.