For the riblets, ask your butcher to cut racks of spareribs lengthwise in thirds, then individually. You can sometimes find riblets sold in Asian markets. Most shrimp paste is fermented. This brand has been cooked in aromatics and stored in oil, so a foundation of flavor has been built in from the process and the saltiness is mellower. If substituting with regular shrimp paste, be mindful of the saltiness and add in increments while tasting.