Remove the stems and seeds from the chilies. Soak them in boiling water for about 20 minutes, until they are plump and soft. Drain well.
While the chilies soak, toast the cumin and coriander seeds in the skillet over medium heat until they are fragrant. Allow to cool, then grind to a fine powder.
Add the drained chilies, cumin, coriander, garlic, salt, and olive oil to the work bowl of the food processor, and pulse until the mixture is a smooth paste. Transfer to a clean jar with lid and top off with a little more olive oil. Will keep in the refrigerator for up to 3 weeks.