Stir fry pesto in oil until fragrant about 2 minutes. Add pork and saute until no longer pink. Add fish sauce and sugar. The meat will start to brown in four minutes. Remove from heat and stir in peanuts. Peel pineapple and cut into 1/4 slices. Remove the hard core from the center of each slice. Cut the slices into 1 inch squares. Serve a spoonful of pork onto each pineapple square, garnish with chiles and cilantro.