Heat a small skillet on medium high heat. Add the sesame seeds. Toast sesame seeds until fragrant and lightly browned. Do not turn your back on the seeds while cooking, they can easily and quickly burn. Stir often to keep them from burning. You may hear them pop, and some of them may hop out of the pan while cooking. When lightly browned remove from heat and set aside.
Mix melted butter in with the bread crumbs. Heat a large skillet on a medium high, add the bread crumbs, stir often until the bread crumbs get toasty brown. Remove from heat, let cool.
Heat the oven to 400°F. Line a roasting pan with foil. Put a flat baking rack on the lined roasting pan.
Use a meat pounder to lightly pound the chicken breasts between two pieces of wax paper to even out the thickness of the breasts.
Use a microplane grater to grate the zest from the orange. Place the zest in a large bowl. Cut 4 thin round slices from the center of the orange to use with this recipe. Save the rest of the orange for snacking.
Add to the large bowl with the zest, the marmalade, soy sauce, sesame oil, peanut oil, red pepper flakes and salt. Mix well. Add the chicken to the sauce, coating every piece. You can at this point make ahead by 24 hours and let the chicken marinate, or you can go ahead with the recipe.
In a large, shallow dish, mix together the toasted sesame seeds and bread crumbs. Working with the chicken one piece at a time, dredge the chicken in the coating, pressing down on the crumbs to make sure they adhere well. Transfer to the baking rack on the lined roasting pan. Dip the orange slices in the leftover marmalade mix and set on the rack.
Cook at 400°F until the chicken has an internal temperature of 160°F, about 20 minutes. Serve immediately, topped with the orange slices.