Pour 4 cups water into a small pot and bring to a boil over high heat.
While water is coming to a boil, remove and discard the stems from the peppers. Transfer peppers to a bowl.
Carefully pour boiling water into the bowl. Stir the peppers with a spoon to make sure they're all saturated with water.
Cover the bowl with a large plate, aluminum foil or plastic wrap. Let the peppers soak for 15 minutes until softened.
Uncover the bowl and transfer the softened peppers to a blender using a slotted spoon to drain out any water.
Add tomatoes, garlic, salt and 3/4 cup of fresh water. Puree until completely smooth.
This salsa is meant to be fairly spicy. If it's way too spicy for your liking, add in an extra tomato or two to help dilute the heat.
Storage - This salsa will keep in the fridge in an airtight container for 1 to 2 months.
Freezing - To freeze, let the salsa come to room temperature. Place it in a freezer-safe storage bag or container and freeze for up 6 months. When ready to eat, remove the salsa from the freezer a day before and thaw in the fridge.