Cut in half lengthwise a ripe but firm avocado, remove seed.  Remove with teaspoon pulp from one-half of an avocado, macerate to creamy consistency with a fork, mix with one-third as much tomato pulp and fill the seed cavity in each avocado half with this mixture.  Garnish the avocado with pignolias pressing them into the flesh around the edge.  Serve on lettuce leaf with two tomato slices.