For the pork:
Coat the pork shoulder with the dry rub. Refrigerate overnight.
Heat a large cast-iron skillet over high heat. Sear the pork shoulder on all side, and then add the lard and oranges. Reduce the heat to a simmer, cover and cook until the pork is crispy on the outside and soft on the inside, about 2 hours. Transfer meat to a large bowl and shred.
For the tortillas:
Mix together the masa flour with 3 1/2 cups of water in a large bowl until combined. Meanwhile, place a cast-iron skillet over high heat. Roll the masa mixture into small balls and use the tortillas press to flatten the dough into tortillas. Place the tortillas in the skillet for 2 to 3 minutes, and then flip and repeat on the other side.
Serve the shredded pork with sliced jalapenos and sliced radishes on homemade tortillas.