These canape's is easiest to make as squares, but if you use a cookie cutter you can make them in any shape of your choice. For Christmas last year I made stars pastry's, with the red tomato in the middle they looked lovely.
FYI:A canapé (a type of hors d’oeuvre, “apart from the main work”) is a small, prepared and usually decorative food, held in the fingers and often eaten in one bit (http://en.wikipedia.org/wiki/Canap%C3%A9)
What you need:
To start make sure the puff pastry is defrosted (if not it won't "puff").
Roll it out slightly and cut into squares about 2cm x 2cm and put on a baking sheet.
Spread the pesto over the squares.
Then cut the tomatoes in half and take the pips out. Fill the tomato with cream cheese and put it on the pesto covered puff pastry square.
Bake in oven for about 10min @ 180°C or until the puff pastry is puffed and golden brown.
Remove from the oven and place on a platter and serve.