1. Preheat the broiler. In a large bowl, combine the cream cheese with the onion, ketchup, mayonnaise and celery. Fold in the crabmeat and season with Tabasco, salt and pepper.
2. Spread a heaping teaspoon of the crab mixture on each toast to cover the surface. Broil in 2 batches for about 2 minutes, or until evenly browned. Serve hot.