Here's a simple way to cut a mango!
1) Use a plate, a sharp knife, a glass (or cup) with a reasonably thin rim, and a ripe mango
2) Using the knife, cut the mango sides away from the seed
3) Place the edge of the cut mango against the glass rim
4) Slide the mango down, keeping the skin edge firmly against the outside of the glass, with the mango flesh inside the glass
5) Slide the mango all the way down until the skin and flesh separate
6) Tip out the mango flesh onto your plate
7) Enjoy your mango!