Juice the lemons and limes. Add the juice to a container with the shrimp, and place in the fridge for 3 hours, stirring partway through.
During this time, dice the tomatoes, cucumbers, jalapeños, onion, and cilantro. Remove the seeds from the cucumbers by cutting them lengthwise and scooping them out.
Once the shrimp have changed color, add in the additional ingredients and mix them together.
Allow to sit for an additional 2 hours or overnight.