Bring a large pot of salted water to a boil and set a bowl of ice water nearby. Drop the snap peas into the boiling water and blanch for 2 minutes. Remove the snap peas and immediately immerse in the ice water long enough to cool completely, about 15 seconds. Drain and place on a kitchen towel or paper towels to dry.

In a small bowl, combine the sliced fennel with 1 to 2 tablespoons of the dressing and a pinch of salt. Gently toss to coat.

Assemble the salad on a platter with the watercress, fennel, snap peas, orange segments, avocado, and mozzarella. Drizzle with some of the dressing and top with the pistachios. Season to taste with salt, pepper, and a squeeze of lemon, and serve.