Peel the mango and cut it into small, juicy cubes, gently squeezing the flesh to release fragrant juice as you cut through.
Thinly slice the red onion and then soak the slices in cold water for about 10 minutes to mellow their sharpness. Drain well and transfer to a mixing bowl.
Finely chop the jalapeño, seeds included, to add a fiery kick and vibrant green color. Add it to the bowl with the onion.
Squeeze fresh lime juice over the chopped ingredients, giving everything a bright, citrusy aroma. Toss gently to coat evenly.
Add the cubed mango to the bowl, mixing gently so the juicy pieces stay intact and release more flavor into the salsa.
Stir in chopped cilantro and sprinkle a pinch of sea salt, tasting and adjusting the seasoning to balance the sweetness and acidity.
Let the salsa sit for about 10-15 minutes to allow flavors to meld, giving it a vibrant, colorful appearance with a fragrant aroma.
Give the salsa a gentle stir before serving. It should have a chunky, juicy texture with bright, contrasting colors and a lively aroma.