Combine 3 tablespoons soy sauce, leek, onion, 2 tablespoons sesame oil, 1 1/2 tablespoons honey, and black pepper in a bowl. Whisk until fully combined. Add tofu and cover with plastic wrap. Marinate in the refrigerator at least 2 hours.

Whisk 1 1/2 tablespoons honey, light soy sauce, 1 1/2 tablespoons sesame oil, and gochujang together in a bowl. Toss in cucumber, carrots, daikon, and scallions. Cover with plastic wrap and refrigerate slaw until ready to use.

Preheat an outdoor grill to 465 degrees F (240 degrees C) and lightly oil the grate. Add the marinated tofu and grill until browned, about 4 minutes per side. Let cool; chop into 1x3-inch strips.

Toss grilled tofu into the prepared slaw. Wrap in lettuce leaves.