Bring a small pot of water to boil. Use a sharp knife to cut a small “x” through the skin at the bottom of the tomato. Drop the tomato into the boiling water and let cook for about 30 to 45 seconds, or until you can see the skin starting to shrivel a little bit. Remove tomato with a slotted spoon and set aside to cool before peeling. When the tomato is cool enough to handle, use a knife and your fingers to pull back the skin. Cut the tomato lengthwise in half and scoop out the pulp and seeds. Cut ½ inch-thick slices of tomato. In a small bowl, stir together the soy sauce, dulse, ginger, sesame oil, and lemon juice. Transfer the tomato to the bowl and toss to combine. Set aside to marinate for up to 24 hours or use immediately.