Cut the tofu into 1/2 inch (1 cm) cubes. Remove the shrimps’ heads. Shell, devein and wash the shrimp. Drain and mix with 5 tablespoons of rice wine, 1/4 tablespoon of MSG, and 1/2 tablespoon of salt. Let stand.
Dip the tomatoes in boiling water for 30 seconds. Peel, seed and dice them. Dice the tofu and place in a pot of cold water. Bring to boil; remove the tofu immediately, and drain.
Heat wok and add oil, stock, the remaining salt and rice wine, the scallions, ginger, tofu and shrimp. Bring to a boil.
Add the tomatoes and 1/4 tablespoon of MSG. Add the cornstarch-water mixture and cook, stirring gently.
When the sauce returns to a boil, sprinkle with the sesame oil, remove, and serve.