Thaw shrimp, if frozen. Peel and devein shrimp. Cook shrimp in a large amount of boiling water for 1 to 2 minutes or until shrimp are opaque, stirring occasionally. Drain; rinse under cold running water.
In a large bowl, stir together ketchup, lime juice, and hot pepper sauce. Add shrimp, tomato, onion, and cilantro; toss to coat. Cover and chill for at least 2 hours or up to 4 hours.
Just before serving, add avocados; toss to coat. If desired, garnish with lime wedges and flowering kale. Makes 8 appetizer servings.