Peel and pit the lychee. Zest the limes and reserve zest as a garnish, then cut the remaining peel off the limes. Add limes, lychee, salt and pineapple to the blender and blend until completely smooth.
Pour puree onto a rimmed baking sheet or into a cake pan or lasagna pan and place in the freezer. After 1 hour, remove from the freezer and scrape and mash with a fork to make little ice crystals. Return to the freezer. After another hour, remove from freezer and mash a second time. Return to freezer. After a third hour, remove from the freezer and mash a final time.
Store in the freezer until ready to serve.
Notes
To transport: transfer to a freezer-safe container that will work for transport. Transport in a cooler and freeze immediately upon arrival. Before serving, give one final scrape/mash with a fork. Serve garnished with lime zest.
Recipe by A Squirrel in the Kitchen at https://asquirrelinthekitchen.com/the-paleo-approach-dinner-club-review-pineapple-lychee-granita-recipe/