Crispy wontons are all about the temperature of the oil. If the temperature is too low, the wontons will soak up the oil and become greasy. If the temperature is too high, the wontons will cook on the outside but not on the inside! To get crispy wontons, heat the oil to 350 degrees. Fry a few wontons at a time - don't crowd the pot. Use a deep-fry thermometer monitor the temperature and increase/decrease the heat as needed.