Combine all vinaigrette ingredients in a blender except for the olive oil; puree. With blender running, slowly add olive oil. Season to taste with salt and freshly ground black pepper. (you can make this a day ahead and refrigerate)
Place potatoes in a large saucepan and add water to cover by 1-inch, sprinkle with salt. Bring to a gentle boil and cook for 10-15 minutes until potatoes are tender. Drain and let cool for 5 minutes.
Meanwhile, fill a 13" x 9" baking dish halfway with ice water. Cook asparagus in a large skillet of boiling, salted water for about 4 minutes. Transfer asparagus to ice water to cool. Drain asparagus and pat dry. Dry baking dish with clean dish towel. Transfer asparagus and reserved potatoes to the dish. Add 1/4 cup of the vinaigrette and gently toss to coat.
In a separate bowl, add radishes and pea shoots. Toss with just enough vinaigrette to coat.
Spread radishes and pea shoots on 1 large platter or 4 individual plates. Arrange potatoes, asparagus, eggs, and tuna on greens. Drizzle lightly with vinaigrette. Serve.