Peel and slice the avocado and place in a large bowl with the shrimp.
In a blender combine the oil, cottage cheese, onion, white vinegar, lemon juice, garlic, and cayenne pepper. Mix well.
Pour the dressing over the avocado and shrimp; mix gently, cover and refrigerator overnight.
Prepare the spinach or greens in a large bowl. Pour the shrimp mixture (don’t add too much) over the greens; gently mix. Optional to serve the greens separate from the shrimp mixture, and let guests dress their own salad.