Pico de gallo will have a lot of juice once it’s complete due to the water content in the tomatoes. Using the roma tomatoes will help to minimize some of the liquid. These juices are also what help the flavor seep throughout the entire dish, so a little bit in the bowl isn't a bad thing. If there is too much moisture you can carefully strain some of it out. You may also want to use a fork or slotted spoon to dish up the pico into individual dishes for serving.