In A Large Saucepan, Heat 2 1/2 Cups Water To A Boil Over Medium-High Heat. Dissolve Bouillon In Boiling Water. Add Shrimp, Green Onion, Soy Sauce And Salt. Boil For 3 Minutes. Dissolve Cornstarch In Cold Water; Stir Into Shrimp Mixture. Cook Until Sauce Is Thick, Then Add Tomatoes And Snow Peas. Serve Hot.