Preheat the oven to 425 degrees F.
On a rimmed baking sheet, combine the chicken, 2 tablespoons olive oil, the garlic, oregano, cumin, cayenne, orange juice + zest, lime juice + zest, and a large pinch each of salt and pepper. Toss well to evenly coat the chicken.
Add the onions, potatoes, and bell peppers, and toss with the remaining 2 tablespoons olive oil and a pinch each of salt and pepper. Arrange everything in an even layer.
Add the orange slices and then transfer to the oven. Roast for 40-45 minutes, tossing halfway through cooking until the chicken is cooked through and the potatoes golden.
Meanwhile, make the salsa. Combine all ingredients in a bowl and toss to combine.
To serve, top the chicken with the salsa. Eat!
