For the chicken: on a cutting board, cut each chicken breast in half horizontally, to form 4 thinner chicken pieces.  Combine all of the marinade ingredients together in a lidded bowl and add the chicken breast pieces, flipping to coat completely in the marinade.  Marinate for at least 2 hours and up to overnight.

Preheat the oven to 400°.  Lay the bacon in a single layer on an aluminum-foiled lined baking sheet and bake until crispy, about 12 to 16 minutes.  Drain on paper towels.  Reserve the bacon fat.  Cut the bacon in half when cooled slightly.

When ready to cook the chicken, preheat a large skillet over medium heat.  Add about 2 tablespoons of bacon fat and cook the chicken breasts for 3 to 4 minutes per side.  When you flip the chicken breast, place 4 halved pieces of bacon and a small handful of cheese on top.  Cover the pan and allow to melt while the chicken finishes cooking.  Alternatively, you can melt the cheese in the oven, if necessary.

To assemble the sandwiches, spread the Honey Mustard-Ranch Dressing on each side of the buns and layer the spring greens, onion and tomato slices on the bottom.  Place one piece of chicken on top and repeat with the remaining sandwiches.