I recently answered a question from a person who was looking to find out how they should choose, eat, and prepare Prickly Pear fruit. Here is the advice I provided and some links to additional info and recipes for Prickly Pears.
Generally there are two common types of prickly pear fruit, the green and red cactus fruit. First try to choose (red) prickly pears that are reddish-orange to purple in color and free of mold spots as these tend to be the sweetest of the prickly pears.
The seeds are fine to eat just be careful when biting into them because these little guys are quite hard.
If you bought your prickly pear from the grocery store they are most likely without larger spines, however, there still remains very small, hard to see spines. You can try putting the pear in a bowl of cold water which helps to remove some of the spines but using something to hold the pear other than your bare hands is always recommended (highly recommended).
Often times the spines are so small you can't see them and this means that when they stick into your hand it will be hard to find them as well. I've spent too much time under a strong light with a pair or tweezers trying to pull these small, very painful spines out of my fingers.
Despite this minor hassle, the prickly pear fruit is worth checking out just remember to use something (plastic bag, paper towel, etc.) to pick up the fruit at the store and while preparing it to eat.
To get to the fruit/flesh simply cut off both ends of the pear (top and bottom), make an incision down the length of the pear cutting into the skin just until you get to the meat and then simply peel away the outer layer. You should be able to role the tough outer skin right off the meat of the fruit. Then enjoy anyway that you like. Check out this episode of Produce Picker Podcast which shows how this techique is done!
The flavor has been likened to kiwis, berries, or a tart watermelon but I don't seem to get this same impression, I'd rather just eat a kiwi. There are however several ways to prepare the prickly pear fruit which make it more interesting and quite flavorful. For instance check out this cool recipe for prickly pear sorbet!
Prickly Pear Sorbet Recipe
Andy Boy Cactus Pear Cheesecake
Prickly Pear Cactus Video
Photo By Wandering Chopsticks
Ray a.k.a. The Produce Picker