Cut the zucchini into halves lengthwise, then slice each half into quarters. Mince the onion and soak it in water for 10 minutes, then squeeze out excess water. Julienne the shiso leaves.

Season the pork belly slices with salt and pepper. Place a zucchini slice on each pork belly slice and roll it up tightly. Repeat to make 8 rolls.

Heat salad oil in a pan over medium heat. Place the rolls seam-side down and cook until browned, turning occasionally. Remove excess oil with a paper towel, add 1 tbsp water, cover, and steam on low heat for 4–5 minutes.

In a bowl, mix lemon juice, salt, pepper, and olive oil. Add the minced onion and julienned shiso leaves to create the lemon onion sauce.