Peel the avocado, cut into pieces and mash with a fork into a coarse puree. Add sour cream, season with pepper sauce, salt and black pepper to taste. Stir in finely chopped zest and green onion.
Dry the slices of bread in a toaster or in a dry frying pan. Brush with avocado paste and top with ham slices. Garnish with cilantro leaves.