Juice 4–6 fresh limes and 1 lemon into a mixing cup, aiming for about ¾ cup of liquid. Remove seeds.

Blend 2 cloves of garlic, a handful of cilantro, 1 diced jalapeno, half of the diced cucumber, and half of the citrus juice for about 30 seconds until smooth.

Chop 1 pound of shrimp into bite-size pieces and add to the marinade with the remaining citrus juice.

Fold in diced red onion and the rest of the cucumber into the shrimp mixture.

Cover the bowl and refrigerate for 30 minutes to marinate.

Gently fold in 1 diced avocado and sprinkle with Tajin before serving.