In a small saucepot, combine the honey, red wine vinegar, and chile de arbol. Heat over medium heat. Allow to reduce for 10 minutes. When the consistency is thick and coats the back of a spoon, remove from heat and set aside to cool.
Meanwhile, in a bowl, combine the plum, red onion, yellow tomato, scallion, cilantro, lime juice, olive oil, and reserved vinegar and honey reduction. Mix well. Season with salt and pepper and set aside.
In a skillet, heat 1 tablespoon oil over medium high heat. Season duck breast with salt and pepper on both sides, and sear, skin side down, for 3 minutes. Place duck breast in the oven, with skin side down, for 10 minutes. Remove from the oven and allow to sit on a cutting board for 3 minutes. Then slice breast in 1/4-inch slices. Fan out on a plate and serve with plum salsa on top.