Add chicken to a large bowl along with all marinade ingredients (lemon juice, garlic, Dijon mustard, onion powder, garlic powder, paprika, dill weed, oregano, thyme, honey) and mix well until chicken is coated
Salt the chicken and let sit in the fridge while preparing rice
Add rice, sliced onion, and mushrooms to an oven tray
Mix in remaining rice ingredients (olive oil, lemon juice, salt, dill weed, garlic powder)
Add a baking rack on top of the oven tray and place marinated chicken on the rack
Preheat oven to 425F and cook chicken and rice for about 30 minutes until chicken thighs reach 165F internal temperature
Let chicken rest after cooking
While chicken cooks, make tzatziki sauce by adding Greek yogurt, grated cucumber, fresh dill, lemon juice, grated garlic, tahini, olive oil, honey, and paprika to a bowl and mix well
Serve chicken and rice with tzatziki sauce
