Thread the squid rings and tentacles (through the fleshy part) on bamboo skewers, leaving about 3 inches for a handle. Wrap the handle in aluminum foil (or soak skewers for 1 hour in water before using.) Combine cumin, coriander and hot peppers. Toast in a dry skillet until fragrant; grind go a powder. Mix well with fish sauce, lime juice and brown sugar. Add squid, marinate on a tray 30 minutes, turning from time to time. Meanwhile, get a hot fire going on a grill, and make a dip sauce by combining remaining ingredients. Grill squid about 90 seconds on each side. Serve with dipping sauce on the side.