Preheat oven to 450F.
Trim ends, slice zucchini lengthwise, and then score them diagonally with a sharp knife. Be careful with the knife.
On a plate, sprinkle kosher salt over the scored top of the zucchini. Let rest at room temperature for 20-30 mins. Then, blot the excess moister from the zucchini using a paper towel. This will help to ensure a golden-brown finish.
In a cast iron or grill pan. Add enough avocado oil to coat the bottom of the pan.
Over medium-high heat, cook the zucchini scored side down for 5-6 minutes.
Flip the zucchini and cook scored side up for 2-3 minutes. Flip one more time, scored side down and place in the oven at 450F for 5 minutes. Remove from oven and plate with the scored side up and serve.
These are delicious straight out of the oven. Season to taste with fresh ground black pepper.