Add the chocolate and peanut butter to a medium sized bowl. Melt gently over a pan of simmering water or in the microwave ( in spurts of 30 seconds). Stir till shiny and combined.
Mix in the puffed rice and amaranth. Pour by small teaspoonfuls in a silicon mould or in mini muffin paper molds set in a mini cupcake tray. Sprinkle some sea salt on top. Tap the tray to release any air bubbles. Pop it in the freezer or refrigerator, until the chocolate is completely set. Take out of the mold and serve immediately. Store any leftovers in the freezer or refrigerator.