1. In a bowl, stir together tomato and chili cocktail mix, tequila, lime juice, onion, cilantro, and 2 teaspoons chili.
2. Pit and peel avocados; cut into 1/2-inch cubes. Add avocados and shrimp to cocktail mixture. Mix gently and add salt and more chili to taste.
3. If desired, rub rims of 4 to 6 margarita or martini glasses with a lime wedge. Immediately dip into a dish filled with 1/4 inch kosher salt.
4. Spoon avocado-shrimp cocktail equally into glasses. Garnish with lime wedges and serve with tortilla chips or saltine crackers.