Heat olive oil in a large skillet over medium-high heat.
Season chicken cubes with sea salt and black pepper, then brown in the skillet until golden on all sides.
Remove the chicken from the skillet and set aside; add the diced onion, bell pepper, and minced garlic to the same pan.
Sauté the vegetables until softened and translucent, about 3-4 minutes.
Stir in the tomato paste, dried oregano, and ground cumin, cooking for 1 minute until fragrant.
Add the dry white rice to the skillet, stirring for 1 minute to lightly toast the grains and coat them in the sofrito mixture.
Pour in the chicken broth and return the browned chicken to the skillet, stirring to combine.
Bring the liquid to a boil, then reduce the heat to low, cover with a tight-fitting lid, and simmer for 15-18 minutes until the rice is tender and the liquid is absorbed.
Remove from heat, let stand covered for 5 minutes, then fluff with a fork and garnish with fresh cilantro before serving.