Rinse shrimp under cold water, pat dry, and if large, cut into 1/2- to 3/4-inch pieces. Smaller shrimp may be left whole or halved. Place shrimp in a nonreactive bowl (glass or stainless steel).

Marinate in citrus

Pour the fresh lime juice and lemon juice (if using) over the shrimp until fully submerged. Stir in kosher salt and black pepper. Cover the bowl and refrigerate. Let shrimp 'cook' in the citrus for 20–30 minutes for small shrimp or until shrimp turn opaque and firm (larger pieces may need up to 40 minutes). Check texture after 20 minutes to avoid overcooking.

Prepare Vegetables & Fruit

While shrimp marinates, finely dice the tomato (remove seeds if you prefer less liquid), very finely dice the red onion and cucumber, and mince the jalapeño (remove seeds for milder heat). Place these in a separate bowl and toss with the chopped cilantro to combine.

Gently dice the avocado and keep separate until shrimp is ready to prevent browning and avoid squashing.

Combine and Finish

When shrimp are opaque and firm, drain about half of the citrus marinade (leave enough to lightly coat — roughly 2–3 tablespoons) to prevent the ceviche from becoming too watery. Add the marinated shrimp to the bowl with the vegetables.

Gently fold in the diced avocado, drizzle the olive oil, and add hot sauce if using. Taste and adjust seasoning with additional salt, pepper, or a squeeze of lime. Stir in most of the chopped cilantro, reserving a little for garnish.

Chill the combined ceviche in the refrigerator for 5–10 minutes to let flavors meld, but serve cold soon after (avoid long storage since avocado and the texture are best fresh).

Serve the ceviche bowl with tortilla chips or on tostadas, garnished with remaining cilantro and lime wedges on the side.