Shrimp Cocktail - Rick Bayless

Ingredients

• 1 generous pound peeled and deveined smallish shrimp (I prefer ones that are about 41/50 count to a pound) OR about 12 ounces cooked peeled and deveined smallish shrimp
• 1/2 cup ketchup
• 1/3 cup fresh lime juice
• 1/3 cup clam juice (or, if cooking raw shrimp, use the poaching liquid)
• 2 to 4 tablespoons vinegary Mexican bottled hot sauce (like Tamazula, Valentina, Búfalo or a chipotle-flavored one
• About 2 tablespoons good olive oil, preferably extra virgin (optional but recommended to smooth out sharpness)
• Salt
• 1/2 medium white onion, chopped into ¼ inch pieces and rinsed, plus a little extra for garnish
• 1/3 cup chopped fresh cilantro, plus several sprigs for garnish
• 1 avocado split, pit removed, flesh scooped from the skin, cubed
• Tostadas, chips or saltine crackers for serving