1. Preheat oven to 400 degrees Fahrenheit. Coat a 9 x 13-inch baking dish with nonstick cooking spray.
2. Using a serrated knife, carefully cut three to four slits into each chicken breast, not cutting all the way through. Carefully arrange breasts in a single layer in prepared dish.
3. Cut each slice of salami in half, forming half-moons. Tuck one to two half-moons into each slit.
4. In a medium bowl, stir together ketchup, vinegar, honey, soy sauce, garlic, and chili flakes.
5. Pour on sauce to coat chicken and salami on all sides. Push chicken pieces together so that salami is securely in place.
6. Bake, uncovered, for 30–35 minutes, depending on the thickness of the chicken, until juices run clear.
Salami Chicken Bites: Cut chicken into two-inch pieces; place into a medium bowl. Add salami “moons” and remaining ingredients; mix well. Arrange in a single layer on a parchment-lined baking sheet. Bake, uncovered, for 15–20 minutes, until chicken is golden. Using toothpicks, pierce chunks of chicken and salami; place onto a serving platter. Serve family style, on individual plates, or as an appetizer for a party.