Season both sides of the chicken thighs generously with salt and freshly ground black pepper.
Heat the vegetable oil in a large nonstick skillet over medium-high until shimmering.
Arrange the thighs smooth-side down without overcrowding the pan and cook 4–5 minutes until lightly browned; flip and cook another 3–4 minutes until the second side is browned. Transfer the chicken to a plate and set aside.
Reduce heat to medium, add the chopped onion and minced garlic, and sauté 2–3 minutes until fragrant and beginning to soften, scraping up any browned bits from the pan.
Add paprika, kosher salt, ground cumin, ground ginger, cinnamon, turmeric, and crushed saffron; stir until the onions and garlic are evenly coated with the spices.
Stir in the orzo to coat it with the spiced onion mixture.
Pour in the chicken stock and bring the mixture to a simmer.
Return the chicken thighs to the skillet, nestling them into the orzo in a single layer.
Continue to cook, stirring occasionally to prevent sticking, about 8–10 minutes, until the orzo is al dente and an instant-read thermometer inserted into the thickest part of the largest thigh registers 165°F (74°C).
Stir in the lemon juice, lemon zest, and sliced olives, then remove the skillet from the heat.
Spoon the chicken and orzo onto plates and sprinkle with the chopped parsley before serving.