For the best flavor, choose small- to medium-sized beets that are firm. Just before cooking, wash beets gently so as not to pierce the skin, which would result in the loss of color and nutrients. Peel the beets after they are cooked and cooled. The skin comes off very easily. Nopales, or fresh cactus, is the fleshy, paddle-shaped stem of the prickly pear cactus. All varieties of prickly pear are edible, but it is best to look for a medium-sized variety that is relatively spineless (this is probably what you would get in the United States anyway). What we see growing in the southwestern part of the United States are generally thick-skinned, low-growing varieties that are not particularly tasty. Nopales are very common in Mexico and are beginning to have more of a presence in the States, as they are very healthy.