In a small saucepan, place the water and agar-agar flakes, and simmer for 5 minutes to thoroughly dissolve the agar-agar flakes.
In a food processor, process the tofu and vegetable oil to a smooth puree.
Add the dissolved agar-agar mixture, soy milk, sweetener, and vanilla, and process for 1-2 minutes or until very smooth and creamy.
Taste and add additional sweetener or vanilla, if desired.
Transfer the mixture to the ice cream maker and freeze according to the manufacturer's instructions.
(Or, if you don't have an ice cream maker, pour the mixture into a large shallow pan, and place it in the freezer. Stir the mixture every hour or so to give it a smooth texture. When completely frozen, remove it from the freezer, and allow it to sit at room temp).