Cook the whole wheat penne in boiling salted water until al dente, then drain and set aside.
Season the chicken thighs with sea salt and black pepper on both sides.
Heat olive oil in a large skillet over medium-high heat and sear the chicken until golden and cooked through, about 5-7 minutes per side.
Remove the chicken from the pan, let it rest for a few minutes, and then slice it into bite-sized strips.
In the same skillet, sauté the sliced bell peppers and onions until they are tender and slightly caramelized.
Stir in the minced garlic and dried oregano, cooking for one minute until fragrant.
Pour in the tomato puree and simmer the sauce for two minutes to meld the flavors.
Add the cooked pasta and sliced chicken back into the skillet, tossing well to combine and heat through.
Serve warm, garnished with a sprinkle of fresh parsley.