Place the oats in a bowl and cover with hot water for at least 30 minutes, or up to two hours. Longer and you risk the dreaded slime.
Drain and rinse the soaked oats in a fine sieve. Add to a tall container or blender along with the water, oil, and salt. Blend, using a hand blender or regular, for 3-5 minutes or until very smooth.
Pour the cream back through the fine mesh sieve and use a spoon to gently scrape until only oat goop remains. You can add the remaining oat mixture to bread, or compost it. It is possible to use a nut milk bag but this can contribute to an undesirable texture.
Pour the cream into a jar or container and seal. Keep refrigerated for up to one week. It might last longer, but I haven't tried keeping it over a week.
* Grape seed is my oil of choice here. See above for more discussion on this, but avoid any oils that solidify easily. Olive oil is fine for savoury uses, and sunflower or organic canola oil also work.