Slice the cherry tomatoes and onion thinly.
Moisten the oatmeal with water until it's soft.
Spread the oatmeal in a pan and cook until golden on both sides.
Top the cooked oatmeal with tomatoes, onions, and lettuce.
Drizzle a bit of olive oil and sprinkle some salt, if desired.
Cover with another piece of oatmeal to make a sandwich.