Season the chicken with 1 teaspoon of salt, or to taste, and black pepper.
Heat the oil in a large non-stick, 12-inch skillet or casserole over medium-high heat. When the oil is hot but not smoking, brown the chicken pieces for about 2 minutes on one side. Flip to the other side and stir in the onion; cook until the onions are completely softened and beginning to brown, about 6 to 8 minutes, stirring the onions often. Add the garlic; and cook for another minute.
Add the poblano chiles and cook another 2 to 3 minutes. Stir in the potatoes and give the entire mixture another good stir. Add the prunes. Pour in the water, add the remaining 1/2 teaspoon of salt (or to taste) into the mixture, cover and cook for 12 to 15 minutes more, stirring once or twice in between.
Meanwhile, toast the seeds. Place a small, sauté pan over medium-low heat. When hot, add the pumpkin and sunflower seeds, stirring often and taking care not to burn them, until you hear popping sounds and they begin to brown lightly, about 3 to 4 minutes. Remove the seeds from the heat and place in a small bowl.
Once the chicken is ready, add the pumpkin and sunflower seeds, gently mix. Taste for seasoning and serve.