1. For vinaigrette: Whisk together zest and juice of 1 lemon, 1 Tbsp rice wine vinegar, 1 tsp Dijon mustard, 1 tsp maple syrup, 1/4 tsp fine sea salt and 1/4 pepper. Slowly add 1/4 cup extra-virgin olive oil, whisking constantly.
2. Bring a large saucepan of salted water to a boil; place a large bowl of ice water next to stovetop. Cook 1 lb asparagus, ends trimmed, tips intact and spears cut into 1-inch pieces, 2-4 minutes or just until crisp-tender. With a slotted spoon, tranfer to the ice water. When cool to the touch drain well and spread on a towel to absorb any remaining water.
3. Combine asparagus and 3 cups cooked white quinoa in a large bowl. Toss with enough vinaigrette to coat all of the ingredients, about 1/4 cup. Add 1/3 cup thinly sliced scallions, 1/4 cup packed fresh mint leaves, finely sliced and 1/4 tsp each salt and freshly ground peppper; toss again. Add more salt, pepper and/or vinaigrette to taste. Serve warm or at room temperature. Serves 4-6