In a small bowl, combine 1 cup raw cashews and water to cover. Soak overnight. Drain cashews. In a high speed blender, combine cashews, 1/3 cup water, 1 teaspoon apple cider vinegar, ½ teaspoon fresh lemon juice, and 1/8 teaspoon coarse salt. Cover and blend until smooth, adding more water as necessary, 1 teaspoon at a time, to reach desired consistency. Makes about 1 cup.