Place the flesh of the avocado in a blender (or small bowl if using an immersion blender). Add the juice of the lemon(s), salt, and pepper to taste (I used about 1/2 teaspoon of salt and a few good dashes of pepper). Add about a 1/4 cup of water at this point, and then blend until smooth. Gradually add another tablespoon of water (or lemon juice) at a time until it reaches your desired dressing consistency. Taste and adjust seasonings if needed. Use right away, or store in an airtight container in the refrigerator for up to 3 days.