Drain the juice from the cans of pineapple and reserve for smoothies or other uses.
Lay the pineapple rings on the grill and let them stay there, undisturbed for 2-4 minutes, or until there are clear grill marks. Use a wide spatula to flip the rings and grill the second side for 2-4 minutes, or until the second side also has obvious grill marks. Use the spatula to transfer the pineapple rings to a rimmed plate to cool until comfortable to touch.
Toss with the remaining ingredients and cover with plastic wrap. Refrigerate from 10 minutes to overnight to let the flavours blend before serving. Toss before serving, taste, and adjust salt if needed. Serve with tortilla chips, alongside grilled pork, chicken, beef, or fish or on pulled pork sandwiches.
Leftovers are good for up to four days in the refrigerator.