In a medium bowl, combine olive oil, tomato paste, minced garlic, lemon zest, lemon juice, salt, pepper, smoked paprika, and oregano or thyme.
Add the marinade to the chicken thighs and mix well to coat.
Let the chicken marinate for 2 to 6 hours or overnight.
Preheat the oven to 210°C.
Place the chicken on a wire rack and roast in the oven for 20-25 minutes.
While the chicken is cooking, prepare the green sauce by processing Greek yogurt, mint, spring onions, jalapeño, olive oil, lemon juice, salt, and pepper in a food processor.
Once the chicken is cooked, serve it with the herby green sauce.