Pat chicken thighs with a paper towel to remove excess moisture, then season with salt and pepper.
In a large skillet with deeps sides, heat olive oil and garlic over medium-high heat. When garlic turns brown, remove chunks from pan and discard.
Place chicken, skin side down, in the heated pan and cook for approximately 4 or 5 minutes, or until nicely browned. Turn and repeat on the other side. Cook for an additional 5 minutes. Remove the chicken from the pan and keep warm.
Pour off excess fat in pan, while reserving approximately 2 tablespoons. Reduce heat to medium and add the orzo to pan. Stir until orzo is coated and slightly toasted. Add chicken broth to skillet and stir to scrape up brown bits from bottom of pan.
Increase heat to medium-high and bring broth to a boil, then reduce heat to low. Return chicken breasts to skillet along with lemon zest and slices. Simmer, covered, for approximately 10 minutes or until the orzo is tender. Keep an eye on it during this time to make sure there is enough liquid in skillet to keep orzo from sticking to the bottom. Stir occasionally.
Uncover and continue simmering until most of the excess liquid has been absorbed, approximately 2-3 minutes. Stir in chopped parsley and season with additional salt and pepper, if desired.
Serve immediately with freshly grated Parmesan cheese, if desired.