Combine the pork, pineapple, feta, pepper, soy sauce, minced garlic, granulated onion, and granulated garlic in a large bowl until well mixed.
Form into 8 patties then refrigerate while the griddle heats.
Prepare a griddle for indirect heat, 325 to 350 degrees F (163 to 177 degrees C).
Cook the burgers until an internal temperature of 175 degrees F (79 degrees C).
Move the burgers to the cooler side of the barbecue and place a slice of cheese on each. When the cheese is melted, remove them from the grill and top them with the onions.