Preheat your oven to 400°F (200°C)
Rinse dry quinoa under cold water until water runs clear
In a large bowl, toss asparagus and radishes with 1/4 cup olive oil, salt, and pepper
Spread evenly on a rimmed baking sheet; roast for 18-22 minutes until tender
While vegetables roast, make the dressing by whisking together lemon juice, 2 tsp olive oil, garlic, maple syrup, and salt
In a separate large bowl, cook quinoa in double its volume of boiling water until tender and fluffy, about 15 minutes
Drain quinoa and let cool slightly
When vegetables are done, transfer to the quinoa bowl; toss to combine
Pour dressing over the top and mix gently
Finish with chopped pistachios, herbs, and scallions before serving