Lightly grease an 8 x 8-inch (20 x 20 cm) baking dish, then line it with parchment paper so that the paper hangs over the edges of the pan on two sides. In a large bowl, combine the brown rice crisps, ½ cup (75 g) of the chocolate chips, and the peanuts.

Heat the agave nectar, peanut butter, flaxseed, coconut oil, and vanilla in a small saucepan over medium-low heat until the mixture starts to liquefy. Whisk until smooth, then remove from the heat and pour over the cereal mixture. Fold everything together until there are no dry pockets and the cereal is evenly coated.

Transfer the mixture to the prepared baking dish, and pack it into an even layer using a spatula. Refrigerate the bars for 30 minutes or until they have firmed up considerably (they may still be a little flexible). Microwave the remaining ½ cup (75 g) chocolate chips in a microwave-safe bowl until melted, 45 to 60 seconds. Stir melted chips until very smooth, and use a fork to drizzle the chocolate over the tops of the bars. Sprinkle with the coarse salt, and refrigerate again for at least 10 minutes.

Carefully pull the bars out of the dish using the parchment sling. Cut the rectangle in half widthwise, then slice each half into five bars. Store in the refrigerator for up to 1 month.