Roughly chop the thawed shrimp into thirds or quarters. Place the shrimp pieces into a large bowl.
Finely chop the cucumber, red onion, tomatoes, and cilantro.
Remove the jalapeño seeds carefully (preferably while wearing latex gloves) and finely chop the jalapeño as well.
Mix all the chopped vegetables in with the shrimp, and squeeze the lime and lemon juice into the bowl.
Mix together well and season with salt and pepper to taste.
Cover the bowl with a lid and let the ceviche marinate in the fridge for at least one hour and up to 24. (The longer you marinate the better the results will be.)
Serve with your favorite tortilla chips and enjoy :)