Arrange the pita halves on a baking sheet and bake for 5 to 7 minutes until warmed through.
In a large bowl, combine the mayonnaise, lemon zest and Arugula Pesto. Stir in the diced chicken.
To assemble the pita pockets, fill each pita half with the chicken mixture. Top with tomatoes and 1/4 cup arugula and serve.
For the pesto, blend the arugula and garlic in a food processor until finely chopped. With the machine running, gradually add the oil until well blended. Transfer to a large bowl and stir in Parmesan and salt and pepper.