Peel the shrimp.

Once peeled, season the shrimp with salt and pepper.

Blanch the shrimp in boiling water for about 2 minutes, then transfer them to a separate bowl.

If the shrimp are large, cut them in half.

After blanching all the shrimp, let them rest at room temperature.

While the shrimp cool, chop the vegetables.

Slice the onion thinly into half-moons: cut the onion in half, then in half again, and slice thinly.

Peel the cucumber, cut it in half, then slice lengthwise to remove the seeds. Cut each half again lengthwise, then chop.

Chop the tomato, serrano pepper, and cilantro.

Place all the vegetables in a bowl. Once the shrimp are cool, add them to the vegetables along with the Worcestershire sauce, Maggi seasoning, and Clamato juice.

Add the avocado at the end, or let everyone add avocado to their own tostada. I like to add it to the whole cocktail at the end.

Mix everything together and add salt to taste.

Serve with tostadas. Enjoy with a cold beer. I like to make a seafood black sauce—I'll share that recipe here.