Halve the tomatoes, scoop out and discard the seeds. Roughly chop the tomato flesh.
Finely chop the chili.
Halve the salted eggs, scoop out of the shells and roughly chop.
Discard the skin, head and tail of the fish. Flake the flesh.
Roughly chop the scallions, mint and cilantro.
Mix together the tomatoes, chili, salted eggs, fish, scallions, mint and cilantro. Sprinkle with salt and pepper. Toss to blend.
Wrap one heaping tablespoonful of the filling with the spring roll wrapper (see how to wrap spring rolls). Repeat until all the filling has been used.
Heat the cooking oil and fry the spring rolls (in batches if necessary) until browned and crisp. Drain on paper towels.
Serve the spring rolls at once. Recommended dipping sauce: hot and spicy vinegar.