First, peel the skin off the tomato. To do this, make a small cross on the bottom of the tomatoes using a sharp knife. Place them in a bowl and cover with hot water for 2 minutes before transferring them to an ice bath. The skins should easily peel off. Once peeled, use a box grater to grate the tomatoes into a bowl.
Add the olive oil, rice vinegar, garlic and salt, then stir until well mixed.
Spread onto toasted bread. Top with optional ham or prosciutto and serve.
