Dice the fresh pineapple into uniform 1/4-inch cubes and place in a non-reactive mixing bowl.
Finely dice the red onion and mince the jalapeño, ensuring seeds and membranes are removed if a milder heat profile is desired.
Chop the fresh cilantro and add it to the bowl with the pineapple, onion, and jalapeño.
Pour the fresh lime juice over the mixture and sprinkle with sea salt.
Toss the ingredients gently with a spatula until thoroughly combined.
Allow the salsa to rest at room temperature or refrigerated for at least 15 minutes before serving to allow the flavors to macerate and meld.