I look at this sandwich and get hungry immediately. I can't stress how simple this sandwich is to make and how much flavor is packed into it. When I was working in restaurants I learned a lot about sauces but the greatest trick I learned was how to transform normal BBQ sauce into something special. Basic BBQ sauce with a little heat and some honey or agave can make an extraordinary sweet + spicy honey BBQ which goes great with grilled chicken. This particular recipe packs a little more heat in the sauce but its mellowed out nicely by the thick bread and creamy avocado. We eat this one open faced and serve it with chips or a small salad, but if you want to make it into a full sandwich lunch just toss on some bacon and tomato and you will be in a world of flavor.
Start off with your BBQ sauce and add in the chipotle powder, cayenne, and honey. Stir/whisk intensely with a fork to make sure all the powder is mixed in and the honey doesn't stick to the mixing bowl. Set aside for now.
Take your chicken breasts and rub them with bbq sauce. Place them on the grill or griddle and cook until firm to the touch in the thickest part of the chicken. Right before they finish up, lather on some more BBQ sauce and keep warm.
Toast your bread on the grill while its still hot and when its nice and toasted, take it off the grill and spread some BBQ sauce on it. You can also spread your avocado down on the bread now instead of topping it on the chicken, this way it won't slide around as much and is easier to eat.
Place the arugula down on the bread, then the chicken breast, and then add the avocado if you haven't already put it on the bread. Enjoy!