Fresh Shrimp Ceviche

Place the finely chopped raw shrimp in a non-reactive glass or ceramic bowl (avoid metal, which can react with the acid).
Pour the lime juice and lemon juice over the shrimp, making sure every piece is fully submerged in liquid.
Cover and refrigerate for 25 to 30 minutes, stirring once halfway through, until the shrimp turns fully opaque and pink throughout with no gray or translucent spots, which means the citrus acid has fully 'cooked' it.
While the shrimp marinates, combine the red onion, tomatoes, jalapeno, and cucumber in a separate bowl.
Once the shrimp is fully opaque, drain off about half of the citrus juice, reserving the rest to keep the ceviche moist, and discard the excess.
Add the marinated shrimp to the bowl of chopped vegetables and gently toss to combine.
Fold in the cilantro, salt, and olive oil, mixing gently so the shrimp does not break apart.
Taste and adjust salt or add a squeeze more lime juice if it needs more brightness.
Gently fold in the diced avocado last, right before serving, so it stays intact and does not turn mushy.
Chill for another 10 minutes if time allows, then serve cold with tortilla chips or crackers for scooping.

Chop the shrimp small and uniform so the citrus juice can fully penetrate and 'cook' every piece evenly within 30 minutes.

Always use fresh raw shrimp meant for ceviche and keep everything well chilled; do not let the bowl sit at room temperature for more than a few minutes at a time.