Prepare the shrimp

• If using raw shrimp, place them in a bowl and cover with lime juice.
• Let the lime cook the shrimp until opaque.

Chop the vegetables

• Dice the Roma tomatoes, red onion and cucumber.
• Thinly slice the white part of the green onions.
• Finely chop the Serrano pepper and cilantro.

Combine the ceviche

• Add the shrimp, tomatoes, red onion, green onion, cucumber, Serrano pepper and cilantro to a bowl.
• Pour in the lime juice and mix well.
• Season with salt and hot sauce to taste.

Chill and serve

• Let the ceviche rest in the fridge so the flavors meld.
• Serve cold with tostadas or chips.