Cut tofu lengthwise into half, then crosswise into 1/2-inch thick pieces. In a small pot, bring 3 cups of water to a boil. Drop in the tofu & return to a boil. Then quickly empty the tofu into a colander to drain.
Heat a wok & coat with 4 tb oil & the salt. Add tomatoes & saute till soft. Add tofu, garlic & sake. Saute for 2 or 3 minutes. Add water & leek. Reduce heat & simmer for 4 to 5 minutes. Stir in dissolved cornstarch & remaining oil. Simmer for 1 more minute until thick. Add peas just before serving.
