One at a time, run a knife down through each avocado, starting at the top, until you reach the pit; continue cutting around the pit until you reach the point you started.
Twist the two halves of the avocado apart. Remove the pit and discard. Scoop the flesh into a large bowl with half of the chiles and half of the cilantro. Mash coarsely with the back of a spoon or an old-fashioned potato masher. Fold in the apples. Season with salt (usually about a teaspoon) and lime juice.
Set a large cast iron skillet over medium-high heat. Sear one side of the belly for 2-3 minutes. Flip, then add the remaining half of the chiles and cilantro to the pan. Sear for another 2-3 minutes.
Build your tacos by placing seared pork belly on a warm corn tortilla and garnishing with apple guacamole, salsa and cilantro.