Dragon Fruit is a very healthy fruit to eat although the skin of a dragon fruit is not edible and should not be eaten.
Peel the skin off the dragon fruit and throw it away before eating the dragon fruit.
You can slice the dragon fruit in half and eat the insides using a spoon or once you remove the skin from the dragon fruit you can slice the dragon fruit into bite sized pieces to eat.
But once again the skin of dragon fruit is not edible and should not be eaten.