To assemble the salad, add the spinach to bowl, chopped strawberry, walnuts and mix together.
Add of the dressing ingredients to a bowl or jar, and whisk or shake it combine.
Taste the dressing and add more vinegar, salt or sweetener as desired.
If serving right away, dress the salad with as much or little dressing as desired. Start with about 1/2 the dressing and add more as needed. (The dressing recipe makes more than you will likely need for this amount of salad, but it depends on your preference)
Top with sliced avocado and a few cracks of fresh black pepper.