Preheat a BBQ or grill to medium-high.
Mash 1 teaspoon salt and garlic in a small bowl with a mortar and pestle or a spoon until a paste forms. Mix in lime zest, 2 teaspoons lime juice and 1 teaspoon ground chipotle. Rub the paste all over pork place in a non reactive container, cover and place in fridge to marinate for 2 hours or overnight. Remove the pork from the fridge and allow to come to room temperature.
Oil a BBQ or grill grill. Grill the pork, turning occasionally, until an instant-read thermometer inserted in the thickest part reaches 65C, around 13 to 15 minutes. Grill onion and caspcicum, turning occasionally, until charred and tender, around 8 to 10 minutes. Transfer the pork to a clean cutting board and let rest for 5 minutes.
Combine cherries, corinader, the remaining 4 teaspoons lime juice, the remaining 1/2 teaspoon chipotle and pinch of salt in a bowl. Finely chop one slice of grilled onion and stir into the salsa.
Thinly slice the remaining onion and pepper. Thinly slice the pork. Serve the pork and vegetables with the salsa and cheese on tortillas.