Chop everything in a similar size, add to a large mixing bowl, mix thoroughly and allow to marinate in the fridge for at least 2 hours before serving. If you are using raw seafood, marinate in the fridge until the seafood is fully "cooked" through and not raw when you cut into it. The type of seafood and size will change the "cook" time.
Serve with your favorite tortillas chips or pita chips and enjoy!
Notes
Citrus juice will "cook" the raw shrimp. This is why the marinating process is so important and you must allow the ceviche to marinate for at least 2 hours, more if you can. Always be careful when using raw ingredients and make sure it is fully cooked before eating.
It's imperative that you use fresh citrus juice when making ceviche. Not only will it taste better, if you are using raw shrimp this is the only way to ensure the shrimp gets fully "cooked" in the juice.
If you prefer a more mild heat in your ceviche, remove all of the seeds from the jalapeno. And if you like more heat, leave the seeds.
Ceviche is best served cold and...you guessed it...fresh! So plan accordingly. If you do have leftovers, make sure you refrigerate them right away and eat them within 24 hours.
You can also add white fish or crab for even more seafood goodness (cooked or raw). I would recommend all raw or all cooked when preparing.
Make sure to dice the veggies small enough to make the chip dipping easier.