Octopus is very intimidating to prepare. Trust me, it's very easy. The hardest part is finding it at the fish store or supermarket. I have seen them in cryovac packaging in the freezer section. Or, you can order one from the fish monger in your local area. Make sure it has been freshly packaged.
1-2 pound octopus, or small octopuses
1 large onion, sliced thin
Olive oil, enough to cover bottom of pan
Salt and pepper
In large saucepan, place cut onions in olive oil. Slowly simmer the onions until they get transluscent and soft, but not burned.
Salt and pepper the onions. Carefully add the wet octopus into the onion mixture. Now the magic happens. Simmer the octupus by covering the pot to let the octopus steam in its own juices. It only takes about 10-15 minutes for the fork to go right through the cooked octopus.
At this point, I add fresh parsley and squeeze fresh lemon. You can serve it room temperature or cold. You can cut up the pulpo or if you are using small octopuses, serve one each.