In a bowl, combine pineapple, onions, cilantro, lime juice, 1 to 2 Tablespoons of chopped jalapeno (or to taste), and a pinch of salt.* Fully combine all of the ingredients. Taste & adjust with more lime juice, salt, or jalapeno. (Keep in mind that the heat will intensify a little as the salsa sits.)
You can serve the salsa & eat it right away. However, it tastes best after the flavors have had time to mingle and marry. Cover the salsa & refrigerate for 4 or more hours for the best flavors. Serve with tacos, nachos, or tortilla chips for dipping.
Notes
*You can simply combine all of the ingredients in a bowl. Or for even sizes & mixing, put the ingredients into a food processor instead. Pulse a few times to get everything mixed, stopping once or twice to scrape down the sides for even chopping. Store leftovers in an airtight container in the refrigerator. It will keep for about 4 days.