Ladle 1 Tbsp. of canola oil into a heated nonstick sauté pan. As soon as the oil begins to smoke, place 6 oz. of chicken in the pan, skin side down. Cook until the chicken skin is golden brown and crispy. Cook on both sides until just cooked through. Slice into thin strips. Place in a stainless steel mixing bowl. Sprinkle 1 tsp. of ancho seasoning over the top of the chicken. Mix together thoroughly.
Spray the inside halves of the top and bottom of the bun with cooking spray. Place on a heated flat griddle, oiled-side down. Grill until golden brown.
Arrange the bottom half of the bun on a warmed serving plate, browned side up. Spread 1 oz. of drained pickled red onions on top of the bun. Place the warmed chicken on top of the onions. Place a piece of muenster cheese on top of the chicken. Place under a heated salamander to melt the cheese.
Spread 1 oz. of drained pickled carrots out on top of the cheese. Place ¼ oz. of baby arugula on top of the carrots. Drizzle 1 Tbsp. of cilantro mayonnaise on top of the arugula. Lean the top of the bun against the sandwich.