Cut off the bottom end of the tomato.
Core the stem of the tomato with a melon baller.
Give 4 incisions leaving 2cm(little less than an inch) from the bottom of the tomato uncut(making tomato into 8 pieces).
Sprinkle salt between the incisions and let stand for 20 minutes.
Julienne radish into 3cm(an inch) length matchsticks.
Julienne white part of the Asian leek(or green onion) into 3cm(an inch) matchsticks.
Cut coriander leaves(cilantro) into 3 cm(an inch) lengths.
Mix julienned radish with Gochugaru(Korean chili flakes) until the radish is well-colored.
Add coriander leaves(cilantro), minced garlic, fish sauce, lemon juice, and lemon zest(+ sugar if needed). Mix well together.
Gently put the stuffing into the tomatoes. Be careful not to tear the tomatoes apart.
Decorate with lemon zest and coriander leaves(cilantro).
Serve fresh or after 1-2 days of refrigeration(wrap individually and store in a container).