For the dressing: In a blender, add the ingredients in this order: spinach, basil, parsley, parmesan cheese, salt, pepper, garlic, avocado, and shallot. Pour in the lemon juice and olive oil, then blend until smooth, scraping down the sides once, 1 to 2 minutes. The dressing will be very thick to ensure it thoroughly coats hearty greens and vegetables like cabbage and snap peas. If you prefer a thinner consistency, add cold water 1 tablespoon at a time (up to ⅓ cup), blending after each addition, until the dressing reaches your desired thickness.
For the salad: In a large bowl, toss together the snap peas, green onions, cucumber, cabbage, and salt. Add the dressing and toss to coat well.
