Because chile peppers contain volatile oils that can burn your skin and eyes, avoid direct contact with them as much as possible. When working with chile peppers, wear plastic or rubber gloves. If your bare hands do touch the peppers, wash your hands and nails well with soap and warm water.
To toast seeds: In a dry, small skillet, heat the cumin and coriander seeds over low to medium-low heat for 5 to 7 minutes or until fragrant, stirring often or shaking skillet to prevent seeds from burning. Remove from heat; allow to cool before grinding with a spice grinder or a mortar and pestle.