Wash the poblano pepper. If you have a gas stove, turn a burner onto medium heat, then char the pepper on one side for about 5 minutes or until the skin turns black. Flip to the other side and repeat the process, then wrap the charred pepper in a moistened paper towel and let it sit for about 5 minutes. Use the paper towel to loosen most of the burnt skin.
If you don’t have a gas stove, you can do this process under the oven broiler turned to high. Times may vary, so watch it closely.
Once the pepper cools enough to touch, cut off the top, and remove the seeds. Chop the pepper.
Into a food processor, add the pepper, avocado, lime juice, mayo, sea salt and cayenne pepper. Process until smooth, about 20 seconds. Scrape down the sides, and process another 10 seconds. Check the texture. If it’s too thick for your liking, add coconut milk one teaspoon at a time and check the texture again. Adding more coconut milk will yield a thinner sauce.
Adjust the seasonings with salt and cayenne pepper to taste.
Stores in the refrigerator, covered, for about 3 days.