Place the fresh baby kale, mâches rosettes (if available), grapefruit, blood orange, cucumber, and pistachios in a large salad bowl and gently toss to combine. Just before serving, add the smoked salmon and avocado and drizzle with fresh lemon juice.
Drizzle salad with desired amount of vinaigrette and enjoy immediately.
For the Vinaigrette
Add all ingredients for the vinaigrette to the bowl of a small food processor and blend until fully incorporated.