Prepare the chicken: Preheat oven to 350 degrees Fahrenheit. In a small dish, mix two teaspoons each garlic powder, paprika, salt, and pepper with just enough oil to form a paste.

Rub the spice paste all over the chicken. Place in a baking dish and add the onion (whole) and stock. Cover with aluminum foil and bake two and a half hours. When cool enough to handle, shred the chicken, discarding the skin and bones but reserving the pan drippings.

Prepare the acini de pepe: In a pot, heat one teaspoon oil. Sauté the acini de pepe for one minute.

Add one cup water and the tomato sauce and bring to a boil. Add salt and pepper to taste and reduce heat to a simmer. Cover and cook for 20 minutes.

Turn the oven back on (to 350 degrees Fahrenheit). In a bowl, mix acini de pepe with the shredded chicken and reserved pan drippings. Transfer mixture to a 9×13-inch baking dish and cook, covered, for one hour.