Preheat oven 200 F.
Wrap tortillas in foil and leave in oven along with four plates to warm.
To make paste, first place the pumpkin seeds in a large frying pan and toast over medium-high heat. When seeds are golden and puffy remove from heat and let cool completely.
In blender or food processor, blend together seeds, chillies, garlic, onions, cumin powder, lime, salt, pepper, coriander, and half of the water. Blend until a thick paste has formed and then stop, do not over blend. Pour the other half of the water in a sauce pan and pour the paste into a metal bowl that can fit on top of the sauce pan to create a double-boiler. Simmer the water in the saucepan but take care not to over-heat the paste.
Spoon the paste into the middle of the tortillas and roll up. Serve with optional salsa, guacamole, on top and/or vegan sour cream.