Place the first 6 ingredients in a food processor and purée. Transfer to a pot and stir in the pineapple. Bring the sauce to a simmer and simmer 5 minutes, or until the pineapple is tender. Stir in the cilantro, and then cover and reserve on low heat.
Season the pork with salt and pepper. Place the oil in a skillet over medium-high heat. Cook the pork 3 minutes per side, or until just cooked through. Divide the pork among 4 plates, top with the sauce, and serve.