Preheat the oven to 375 degrees F with a rack in the center position. Line a sheet pan with aluminum foil and mist the foil with cooking spray. Spread out the ham on the prepared pan and bake, using a spatula to mix and turn the ham occasionally, until lightly browned, 10 to 12 minutes. Transfer the ham to a plate with a spatula or slotted spoon. Do not wipe up any grease from the bottom of the pan. Place the kale on the sheet pan, drizzle with the olive oil, sprinkle with 1/2 tsp. salt, and toss to coat. Spread out the kale in an even layer. Bake for 5 minutes. Remove the pan from the oven but leave the oven on. Use a wooden spoon to make divots in the kale to accommodate the eggs. Crack an egg into each divot. Sprinkle the feta, the reserved ham cubes, and some salt and pepper on top. Return the pan to the oven. Bake the eggs until the whites are set but the yolks are still runny, 10 to 15 minutes. Enjoy greens and eggs and ham immediately, with some crusty bread to soak up the warm, runny yolks.