For the chicken: Preheat the oven to 450 degrees F and grease a large, rimmed baking sheet. Place the chicken, potatoes and artichoke hearts on the baking sheet. Toss with the 2 tablespoons olive oil, sprinkle with the thyme, salt and pepper, and toss again to evenly coat. Spread in a single layer with the skin side of the chicken facing up.
Roast on the top rack for 30 to 35 minutes or until an instant-read thermometer inserted into the thickest part (avoiding the bone) registers 165 degrees F. (I have also roasted on the middle oven rack. In this case, I broil a minute or two at the end for a little extra crispiness and browning.)
For the quinoa: While the chicken is in the oven, bring the water to a boil in a medium-size pot. Add the rinsed and drained quinoa, cover, reduce the heat and simmer for 15 minutes (check after about 12 minutes) or until the water is fully absorbed. Remove from the heat and allow to rest, covered, for 5 minutes.
Meanwhile, combine the olive oil, vinegar, honey, garlic, chopped olives, salt, and pepper in a small jar or bowl. Put the top on the jar and shake well or whisk together until combined. When the quinoa is finished, spoon a few tablespoons of the dressing over the quinoa and toss. Reserve the remaining amount to serve on the side or for a Greek salad another night.
Serve the quinoa topped with the roasted vegetables and the chicken alongside. Garnish with fresh thyme, if desired.