In a large bowl, combine pineapple, mango, tomato, onion, jalapeño, and cilantro.
Add lime juice, lime zest, and salt. Gently toss to combine.
Cover and refrigerate for at least 30 minutes to let the flavors meld.
Notes
To cut the pineapple: remove top and bottom, slice off the skin, then cut around the core and dice into ½-inch chunks. For mangoes: slice off the sides, score the flesh in a grid, and scoop with a spoon.
Sprinkle on a little chili powder or cayenne for more heat.
The tomato helps to balance the sweetness, but you can leave it out if you prefer.
Store the salsa in a covered bowl in the fridge for up to 4 days. Over time, it may become more watery—just give it a stir before serving.