Spray the chile with cooking oil, and grill on direct heat, turning every few minutes so it gets nicely singed all around. It takes about 8 to 10 minutes to grill.
When the chile is browned and blistered all over, remove it from the grill and set aside to cool.
When the chile has cooled, remove the outer layer of skin with a sharp knife. Start by cutting a slit down lengthwise, then grab and peel the thin skin. Use gloves or take care not to rub your eyes when working with chile peppers.
Once the skin is off the chile, cut it open and remove most of the seeds. I kept a bit of the seeds, perhaps 1/4 of them or so. You can adjust the amount of seeds based on the amount of kick you want for your salsa–it’s the seeds that pack the heat.
Chop the chile flesh and place it in a small bowl along with any seeds you choose to use.
Stir in the remaining ingredients. Let it sit for an hour or so to let the flavors meld. Then you are ready to enjoy!