Preheat the oven to 300° Spread the walnuts on a sheet pan and cook for 10-12 minutes until toasted and fragrant. set aside.
Cook the quinoa according to the package directions -- when it's fully cooked, remove the lid, fluff it with a fork and set aside, uncovered, to cool to room temperature.
Trim the tough ends from the asparagus (usually about the bottom inch or two). Slice the asparagus spears into one inch pieces. Bring a pan of water to a boil. Meanwhile, set up an ice bath -- a medium sized bowl filled with ice and water.
When the water comes to a boil, add the salt and the asparagus pieces and cook for 3-4 minutes until bright green and tender. Use a slotted spoon to transfer the the asparagus to the ice bath to stop the cooking and help it retain it's bright green color. Set aside.
In a large bowl, combine the radishes, peas, cucumbers and olives. Remove the asparagus from the water bath and pat dry with paper towels. Add the asparagus to the bowl. Fluff the quinoa with a fork and check to make sure it's at room temperature and if it is, add it to the vegetables. Toss to combine.
For the Lemon Shallot Dressing
Zest the lemon and transfer it to a small bowl. Add the minced shallot, dijon mustard, whole grain mustard, honey, kosher salt, pepper and the juice from the lemon - about 3 tablespoons. Slowly drizzle in the olive oil, whisking constantly until emulsified. Stir in the chopped tarragon and parsley.
Add about 1/4 cup of dressing to the salad and toss to coat. Salad should be moist but not goopy - so take care not to overdress the salad. Adjust seasoning to taste, adding salt, pepper or more lemon juice as needed. Roughly chop the toasted walnuts and add to the salad just before serving, so they stay crunchy.