eating a lot of cactus

It is interesting to me that cactus is such a staple here in Mexico.  At the market this woman and many others up and down the street are preparing the cactus.  They have a board that they scrape the spines off and she is trimming the edges.  At other stops along the way I see when they grill it or cut it up and put it with other cut up veggies.  Sometimes them batter it and fry it.  Often they put toppings on it and just cut it up and eat it after it has been cooked.  They also put it in corn tortillas along with salsa and eat it that way.