Cut the outer skin of the pineapple off by cutting off both ends. Stand it on one of the flat cut sides and with a knife, carefully cut down the sides all around the pineapple avoiding the pits as well as you can. Slice the pineapple into 1/4 inch planks down the sides, stop once you get to the core. Cut the planks into a very small dice. Place in a bowl and set aside.
Chop the jalapeno, first cut off the stem and slice it open lengthwise. Take out the membrane and seeds on the inside and chop fine. Add to the pineapple.
Finally, slice the green onions very thin, add in the cumin, cilantro, lime juice, salt and pepper. Mix together thoroughly. Taste and adjust seasoning if needed.
Serve with tortilla chips or on top of tacos and enjoy!