Jars of salsa, do I have to boil the jars if they sealed on their own?
Yes, you should fully process your salsa, even if you got the "hot jelly" seal just from hot packing.

The reason for this is that part of the processing is to ensure that the entire contents of the jar, all the way through, is at a high enough temperature for a long enough time to be safe as a shelf-stable product.   This may or may not already be true from the initial cooking down, but in these matters, you absolutely positively want to be sure.