Heat a grill-pan over medium-high. Generously coat pan and avocado with cooking spray. Place avocado on grill pan, flesh-side down, and cook 4-5 minutes, rotating once halfway through, until deep char marks appear. Remove skin and slice in half, either crosswise or lengthwise. Place one half on top of each bowl of oats.
Bring 2 quarts water to a boil in a medium saucepan over medium-high. Gently place egg in water and cook 6 minutes. Remove with a slotted spoon and place in a bowl of cold water. Let stand 2 minutes. Remove shells gently and slice in half. Sprinkle evenly with salt and crushed red pepper flakes. Place one half inside or on top of each piece of grilled avocado.