My salsa isn't watery any more, since I figured out a new method. I take the amount of tomatoes needed in the recipe, cut them in half, and roast them in the oven at 400 for one hour, along with any other veggies required. This evaporates the extra water out of the veggies.
Once they are done, I use the immersion blender to puree. I don't peel or seed the tomatoes.
I just haven't been the same
since that house fell on my sister.