How to Make It
Place the tofu between 2 plates. Weight the top plate with a heavy can and refrigerate for 15 minutes.
Meanwhile, in a medium bowl, combine the chopped kimchi with the soy sauce, 1 tablespoon of the rice vinegar and 1/2 teaspoon of the sesame oil. Drain the tofu and pat dry. Cut the tofu into 1/4-inch-thick slices and then cut each slice into 2 triangles. Arrange the tofu triangles on a platter and spoon the kimchi dressing on top. Refrigerate the dressed tofu for 5 minutes.
Meanwhile, in a medium bowl, toss the cucumbers with the remaining 1 1/2 tablespoons of vinegar, 1/2 teaspoon of sesame oil and the mirin. Season with salt. Scatter the scallions over the tofu and serve right away, passing the cucumber salad on the side.