Bring a large pot full of water to a boil. Fill a large bowl with ice and then cover with water.

Score tomatoes with a shallow "x" on the bottom of each (see picture).

When water is boiling, gently add tomatoes and let cook for 30 seconds, and no longer. Remove from hot water and place in ice water using tongs.

Preheat broiler. Let tomatoes sit in the ice water for a few minutes and then remove and set on a towel. Flesh should be peeling back, and use your hands to totally peel the flesh off of the tomatoes. Set on a foil lined baking sheet, sprinkle with a little kosher salt and set in the broiler until they are a bit black on top. See note.

Meanwhile, set a jalapeno on the open flame of a your stove (if you don't have a gas stove just add it to the baking sheet with the tomatoes, turning half way) turning occasionally until it blackens but doesn't get soft. Set aside.

When tomatoes are done, add to a food processor or blender and pulse or blend quickly until no big chunks remain. Add jalapeno (with seeds for a spicier salsa) and blend again really quickly so incorporate jalapeno but still leave it a little chunky. Pour into a bowl.

Add onion and juice of the 2 limes to salsa and set bowl in fridge until cool.

When salsa is cool add the green onions and cilantro. Season with salt and pepper and put in jars, or cover bowl and keep in the fridge until you're ready to use it. It will stay good for about 4-5 days.