Scald the tomatoes and peel away the skins. Cut a slice off the top of each and, using a teaspoon, scoop out the seeds. Sprinkle with salt and turn the tomato cups upside down to drain.
Using a wooden spoon blend together the cream cheese and lemon juice, then using a tablespoon fold in the caviar. Pile the cheese mixture into the tomato cups and replace the lids. If preferred they can be topped with additional caviar. Serve with thinly sliced brown bread and butter.