Preheat the oven to 350°F (175°C).
Place a medium sauté pan or large ovenproof skillet over medium-high heat. Add 2 tablespoons olive oil and heat until hot.
Add the sliced onion and the diced garlic to the pan. Sauté, stirring occasionally, until the onions just begin to become tender, about 4–6 minutes.
Stir in the contents of the 1 (14.5 ounce) candiced tomatoes and the drained 1 (14.5 ounce) can black olives, spreading the mixture evenly in the pan.
Arrange the 4–6 boneless skinless chicken breasts in a single layer on top of the tomato-and-olive mixture.
In a small bowl, combine 1/2 teaspoon kosher salt, 1/2 teaspoon paprika, 1/4 teaspoon ground cumin, and 1/4 teaspoon ground black pepper. Sprinkle this seasoning evenly over the chicken breasts.
Transfer the ovenproof skillet to the preheated oven (or transfer everything to a baking dish if your pan is not ovenproof). Bake until the chicken is cooked through and the juices run clear when pricked with a sharp knife, about 25–30 minutes, depending on breast thickness.
Remove from the oven, let the chicken rest for a few minutes, and sprinkle with fresh parsley if using before serving.