Mangos contain a large, flat seed that doesn’t separate readily from the juicy flesh, so the easiest way to handle a mango is to cut the flesh away from the seed. Mango flesh can be slippery, so leaving the skin on will help you get a grip.
Balance the mango on one of its narrow sides, and then slice off one of the wide sides of the fruit. Try to cut as close to the seed as possible, usually about 3/4 inch from the center. Repeat with the other wide side and then slice off the remaining strips of fruit from the narrow sides.
To dice the wide pieces of mango, cup one in your palm and use a paring knife to score the fruit into the dice size you want. Try to cut down to but not through the skin, and hold the mango with a kitchen towel to protect your hand in case the knife does pierce the mango skin.
Use your fingertips to pop the mango inside out and then use the paring knife to slice the cubes away from the skin.
To dice the narrow strips of mango, simply trim away the skin and cut.