In a medium sauce pan, head oil over medium heat. Add onion, cumin and cinnamon. Cover and allow onions to softened. About ten minutes or so. Stir in garlic, chili powder, oregano, cayenne, and flour. Whisk in broth and vinegar. Bring mixture to a boil and then reduce heat to allow sauce to maintain a simmer. Stir often until mixture reduces and thickens. About 30 minutes. Remove from heat and allow to cool and thicken.
Chicken
Preheat oven to 450°F.
While sauce is simmering, fillet chicken breast into two. In three separate bowls, divide the flour into one, whisked egg into another and lastly add in toasted panko crumbs. Dip each chicken fillet into flour, dredge in egg and then dip and coat with panko crumbs. Place onto lightly sprayed broiling pan. Repeat with other chicken fillet. Bake at 450 for about 10 minutes or until panko is golden brown and chicken is cooked through. Allow to cool slightly before slicing. Ready for final preparation.
Salad Preparation
Plate two corn tostadas per plate in a stacked fashion. Top with lettuce shreds and spinach. Sprinkle on cheddar cheese. Top with sliced chicken. Pour mole sauce over the chicken and serve immediately.