Cut the cucumber lengthwise, slice thinly at an angle, and mix with salt in a bowl. Let sit for 5 minutes, then squeeze out excess water. Dice the tomato.

Combine the sauce ingredients (☆) in a plastic bag, mix thoroughly, and chill in the refrigerator until ready to serve.

Place pork slices on a cutting board, top with bean sprouts, cucumber, and zha cai, then roll into 10 wraps. Arrange wraps seam-side down on a microwave-safe plate, drizzle with sake, cover loosely with plastic wrap, and microwave at 600W for 3 minutes or until cooked through.