In a small bowl or medium jar, combine the lemon juice, olive oil, mustard, and garlic. Whisk to combine or shake with the jar lid on tight. Season with salt and pepper, to taste, and set aside.: You will smell the bright lemon and sharp mustard immediately, which signals the dressing is lively. Emulsifying until it slightly thickens helps it cling to the quinoa and vegetables. If the dressing separates later, a quick whisk before tossing will bring it back together. Avoid adding too much salt at this point, because the feta cheese will add saltiness later.
Add water, quinoa, and salt to a medium saucepan and bring to a boil over medium heat. Boil for 5 minutes. Turn the heat to low and simmer for about 15 minutes, or until water is absorbed. Remove from heat and fluff with a fork.: As the pot comes to a boil you will hear a steady simmer and see the tiny grains shimmer; this is when they begin to absorb water. After simmering, the surface should show small holes where steam escapes, and the liquid should be mostly absorbed. Letting it sit off heat for a few minutes helps steam finish the job. A common mistake is lifting the lid too often, which releases steam and can make the quinoa unevenly cooked. Fluffing with a fork keeps the grains separate and prevents clumping.
While the quinoa is cooking, cook the asparagus. In a large skillet, heat the olive oil over medium heat. Add the asparagus and fresh lemon juice. Cook until tender, about 5 minutes.: You want to see the asparagus turn a brighter green and hear a gentle sizzle when it hits the pan. As it cooks, the aroma of lemon will lift and the edges may show slight browning, which adds a touch of caramelized flavor. The tips should be tender but still have a bite. Overcooking results in limp, olive colored stalks, so keep an eye on texture by piercing with a fork.
In a large bowl, combine quinoa, asparagus, chickpeas, green onion, and feta cheese. Pour the dressing over the salad and stir until well coated. Season with salt and pepper, to taste. Serve.: When you toss everything together you should see the dressing sheen across the quinoa and vegetables, and the scent of lemon and garlic will be front and center. Stirring gently helps keep the feta cheese crumbles intact while ensuring even distribution. Taste and adjust seasoning, bearing in mind that canned chickpeas and feta cheese carry salt, so start light. A common issue is overdressing, which can make the salad soggy; start with less and add more if needed.
