Boil the potatoes until tender. Allow to cool. Peel the skin from the potatoes. Dice potatoes into small cubes and set aside.
Prepare spices, ginger paste, and green chile. Heat 1/4 cup vegetable oil on medium-heat in a skillet. Add ginger and green chile, and saute for a few minutes. Add potatoes, and spice mixture. Saute until well combined. Taste and add additional salt if necessary. Set aside in a bowl for later use.
To prepare the dough: Using a food processor combine flour, salt, and vegetable oil. Pulse until mixture has become well-combined and the oil is well-incorporated. With the blade running consistently, begin slowly drizzling in the water. The dough should come together into a ball. Turn off the processor and check the texture of your dough. If it is too dry, add a little more water. If too sticky add additional flour. You want the texture to be firm and springy, not sticky or crumbly.
Lightly grease a mixing bowl and allow the ball of dough to rest at least 1 hour. Cover with a damp towel to prevent from drying out. Separate dough into 5 small balls of dough. Return to mixing bowl and allow to rest in the refrigerator for another 30 minutes- 1 hour.
To assemble the samosas: Once your dough is prepared, take 1 small dough ball at a time, and roll out into a thin, oval shape. The dough should be about 1/8 inch in thickness.
Slice in half with a knife to create 2 half moon shapes. Using one of the half-moons, apply water to the straight edge of the dough.
Press the straight edges together to form a cone.
Now, fill the cones using the potato mixture. Fill as generously as you can, with about 2-3 tablespoons of potato mixture. Then add additional water to the rounded edge and completely seal your samosa. You may use a fork to further crimp the edges for added seal. You will make 10 samosas.
Set completed samosas on a lightly greased plate.