Heat butter and water to boiling. Sift flour and salt together. Add flour mixture at once to the boiling water and stir vigorously. Cook and stir batter until is leaves the sides of the pan. Remove from heat and cool slightly. Add unbeaten eggs, one at a time, beating well after each egg. Drop batter into 1-inch rounds onto slightly greased cookie sheet. Bake at 425 F for about 20 minutes, until puffed up and brown. Reduce heat to 350 F and bake for about 10 minutes more with oven door cracked. Remove from oven and cool.
Break up tuna into small pieces. Mash cream cheese into tuna. Combine remaining ingredients and mix lightly. Fill cream puffs with mixture and use for appetizers.