Cut the avocado in half and remove the pit. With a paring knife, gently cut a thin cross-hatch pattern into each avocado half cutting down to the skin, but not cutting through the skin, then use a spoon to scoop out the avocado flesh from the skins.
Toss the chickpeas, corn kernels, and avocado flesh in a bowl and gently toss everything together.
Squeeze the lemon half over the salad, drizzle with olive oil, season with salt and toss again.
If desired, serve in the hollowed-out avocado skins