Trim Edge: Using tongs to hold the cactus leaf, lay it on a flat surface and trim off the entire perimeter of the leaf.
Remove Thorns: Turn your knife perpendicular to the cactus leaf and cut off each of the spikes and raised brown bumps, keeping as much of the cactus skin intact as possible.
Rinse: Rinse the leaf well, ensuring there are no more spikes on it.
Slice: Slice the cactus leaf into either strips or cubes.
Boil: Bring a pot of salted water to a boil. Add cactus, cover, and let simmer until tender, about 8 to 10 minutes.
Rinse: Strain the cactus from the water and rinse again to remove any sliminess.
Serve: From here you can serve the nopales, or saute them into a number of other dishes, like fajitas, tacos, or with eggs!