In a large bowl, combine the olive oil, smoked paprika, cumin, garlic powder, onion powder, salt, black pepper, cayenne pepper, and lime juice. Add the chicken thighs and coat them well with the marinade. Let them marinate for at least 30 minutes or up to 2 hours in the refrigerator for more flavor.
Heat a large skillet over medium-high heat. Add the marinated chicken thighs and cook for about 6-7 minutes on each side, or until the chicken is cooked through and has a nice golden color. Remove the chicken from the skillet and set aside to rest.
In the same skillet, add the sliced zucchini and red bell pepper. Sauté for about 5-6 minutes until the vegetables are tender but still crisp. Sprinkle with dried oregano and red pepper flakes if using, and stir to combine.
Slice the cooked chicken thighs and serve them over the sautéed zucchini and bell pepper. Garnish with fresh cilantro before serving.