Red Chile Chicken Tostadas

Name: Red Chile Chicken Tostadas
Ingredients: 12 corn tortillas; Vegetable oil; Salt to taste; 1 1/2 pounds boneless, skinless chicken breasts, thighs, or a combination; 1 pouch (8 ounces) Frontera Red Chile Enchilada Sauce; 1 ½ cups Salpica Chipotle Black Bean Dip or crushed canned black beans; 1 small red onion, finely diced, rinsed; 1 cup sour cream or plain Greek yogurt, thinned with milk if necessary; 2 or 3 tablespoons chopped fresh cilantro; 2 or 3 tablespoons crumbled Mexican cotija or romano cheese, optional