Cut potatoes into medium slices.
In a large skillet over medium-high heat, heat oils. Add potatoes and season with salt and pepper. Cook, undisturbed, until potatoes are golden and crusty underneath, 4 to 5 minutes. Flip potatoes and cook until golden on other sides, 4 to 5 minutes more.
Continue to cook, stirring occasionally, until potatoes are tender, about 2 minutes more. Set aside.
Whisk eggs, water, salt and pepper.
Heat non-stick skillet over medium heat.
Pour in egg mixture.
As eggs set around edge of skillet, with spatula, gently push cooked portions toward centre of skillet. Tilt and rotate skillet to allow uncooked egg to flow into empty spaces.
When eggs are almost set on surface but still look moist, Slip spatula under half side and fold over onto other half.
Cook for a minute, then slide omelette onto plate.
Serve with fried popatoes.