Place the mashed avocado, cream cheese, and blue cheese in a 2-quart bowl, and blend the mixture with a fork until it forms a smooth paste.
Place the sunflower seeds in a blender, and process at medium speed for 2 minutes, or until finely ground. Stir the seeds and the lemon juice into the avocado mixture.
Use immediately, or place in an airtight container and store in the refrigerator for no longer than 1 day.