Dice the onion and add it to a large mixing bowl with the lime juice.
Slice the top and bottom from your pineapple then slice the skin away and remove any eyes. Cut the pineapple down the middle then quarter and slice away the core. Dice into small pieces and place in a large bowl.
Dice the bell pepper, and tomatoes. Halve the jalapenos and remove the seeds and ribs then mince.
Mince cilantro leaves and place everything into the bowl with the pineapple. Sprinkle salt and stir to combine.The salsa will keep well in the fridge for up to 2-3 days or can be frozen.