How to Make It
Fit a medium pot with a steamer insert. Add 1 inch of water to the pot and bring it to a boil. Add the tuna and steam until cooked through, about 8 minutes. Let cool. Flake the tuna into a medium bowl; don't remove the fat. Gently stir in the cilantro, scallions, butter, green peppercorns, lemon juice and cayenne.
In a small bowl, beat the cream until stiff. Fold the cream into the tuna and season with salt. Transfer to a crock and serve at room temperature or slightly chilled with crackers.