Mexican Shrimp Cocktail

medium white onion

large cloves garlic, coarsely chopped

salt, plus more to taste

freshly ground black pepper

large shrimp, peeled, deveined and tails removed except for 6 to place on top as part of the garnish

ketchup

clam juice

to 3 tablespoons lime juice (or to taste)

Mexican hot sauce,

small jicama, peeled and diced (about 1 cup)

large English cucumber, diced (about 1 cup)

medium avocados, peeled, pitted and chopped

chopped cilantro, loosely packed

lime wedges, for serving

cilantro springs, for serving