Step 1. With stainless-steel knife, cut avocado in half lengthwise around pit. Rotate two halves to separate; the pit will remain in one of the halves.
Step 2. Gently insert knife blade into pit; twist and remove pit on blade.
Step 3. Hold pitted avocado half in hand, or place on cutting board. Cut slices just to, not through, skin.
Step 4. Peel skin back. For guacamole, scoop the avocado flesh out with spoon. Rub exposed flesh with lemon or lime to prevent discoloration.