Marinate the chicken: toss the chicken thighs with the salt, thyme, paprika, oregano, garlic powder, lemon juice and olive oil. Marinate for at least 15 minutes, or cover and refrigerate for a few hours or overnight.
Rinse the rice under cold water until the water runs mostly clear.
Heat the olive oil in a saucepan over medium heat. Cook the onion for 4 to 5 minutes until soft, then stir in the garlic, oregano, paprika and salt for 30 seconds.
Add the rice and stir for 1 minute. Pour in the chicken broth, bring to a boil, then cover and simmer on low for 12 to 15 minutes until absorbed. Rest covered for 5 minutes, fluff, and stir in the parsley and dill.
Cook the chicken in a grill pan or skillet over medium-high heat for 5 to 6 minutes per side, until charred and cooked through to 74°C (165°F). Rest 5 minutes, then slice.
Toss the tomatoes, cucumber, red onion and olives with a squeeze of lemon, a pinch of oregano and salt. Top with feta.
Divide the rice between 4 bowls, add the chicken and salad, and finish with tzatziki and fresh parsley.
Notes
Store the rice and chicken in the fridge for up to 4 days. Keep the salad and tzatziki separate until serving.