The chilies should be dried ( in the oven ) before freezing them . Store them in sealed glass jars in a cupboard, or in the freezer double-wrapped in freezer bags. (Don't put bagged chilies in a cupboard because the plastic is porous and the chilies can oxidize, ruining both the color and the flavor.) With both storage methods, dried chilies last indefinitely.
To reconstitute the chilies, soak them in hot water for about 15 minutes, fry them in a bit of oil until they puff up, or lightly roast them. Dried chilies can also be ground to a powder when you're ready to use them (no earlier, because the powder would lose its flavor).