How to slice an avocado.
Hold the avocado in one hand or place it on a cutting board. Using a chef knife, cut through the center of the avocado lengthwise until the knife comes in contact with the pit. Without removing the knife, make a continuous slice around the pit until the knife meets the initial incision point.
Once the avocado is open hold the piece with the seed in the palm of one hand and a sharp chef knife in the other. Carefully, but firmly bring the blade of the knife down on the center of the seed so the knife is lodged into the seed. Turn the seed 1/4 of the way and lift it out.