In a large ziplock bag, combine the pineapple juice, rice vinegar, hoisin, sriracha, honey, fish sauce, and garlic; seal bag and shake or massage contents well. Add pork tenderloin to marinade in the bag and refrigerate for at least 4 hours or overnight.
Preheat a grill to 375-400 degrees F.
Remove pork from marinade and grill for about 12-15 minutes, turning every 4-5 minutes; remove from grill to a cutting board and cover with foil. Allow meat to rest for about 5 minutes before dicing into ½-inch pieces.
Arrange about 2 ounces of pork onto each of 8 tostadas and top with a few tablespoons of mango and 2 tablespoons of salsa verde. Serve immediately.