In a large pot, bring water to a boil with the lemon peel, salt, and chili flakes.
Let the water boil for 3–4 minutes to soften the lemon peel.
Next, add the asparagus and blanch for 45 seconds to 1 minute.
Remove the asparagus from the water and let cool on a tray.
Strain the water bath, reserving the peel.
Once the asparagus has cooled, season lightly with salt, pepper, and olive oil.
Place asparagus on a hot grill, rotating every 1–2 minutes until grill marks appear on all sides. Remove from the grill and place on a serving plate.