While the oven preheats to 400°F, mince your garlic fresh (I find this makes a noticeable difference in the dressing's aroma), juice the lemons, chop the parsley and mint, and slice the scallions. Lightly toast the pistachios in a dry skillet over medium heat for 2-3 minutes, shaking occasionally, until fragrant—this brings out their natural flavor and adds a satisfying crunch to the final salad.
Start cooking the quinoa according to package instructions (usually about 15 minutes) in a pot. While that cooks, toss the asparagus and radishes with 2 teaspoons of olive oil, season with sea salt and red pepper flakes, then spread on a lined baking sheet. Roast at 400°F for 20-30 minutes, tossing halfway through, until the vegetables are tender and lightly caramelized. Once the quinoa is done, spread it on a plate or baking sheet to cool faster.
While the vegetables roast and quinoa cools, whisk together the 1/3 cup of premium olive oil, freshly squeezed lemon juice, minced garlic, maple syrup, sea salt, and red pepper flakes in a bowl. I like to let this dressing sit for a few minutes so the garlic can infuse the oil—it deepens the flavor significantly. Taste and adjust seasoning as needed.
Once the roasted vegetables have cooled for about 20 minutes, add them to a large bowl along with the cooled quinoa from Step 2. Pour the dressing from Step 3 over everything, then toss gently to combine. Add the chopped parsley, mint, scallions, and toasted pistachios from Step 1, and toss once more until evenly distributed.