01 - Line a baking sheet with parchment paper and set aside.
02 - Toast hazelnuts in a dry skillet over medium heat for 5–7 minutes, stirring frequently until fragrant and skins begin to split. Transfer to a clean kitchen towel, rub to remove most skins, let cool, then roughly chop.
03 - In a large bowl, combine chopped hazelnuts, dates, and crispy rice cereal. Mix well until evenly distributed.
04 - Melt dark chocolate and coconut oil in a heatproof bowl over a saucepan of simmering water using the double boiler method, or microwave in 30-second bursts, stirring until completely smooth.
05 - Pour melted chocolate over the nut-date-cereal mixture. Stir thoroughly until all ingredients are evenly coated with chocolate.
06 - Drop heaping tablespoonfuls of the mixture onto the prepared baking sheet, shaping into rough clusters.
07 - Sprinkle clusters with flaky sea salt if desired.
08 - Refrigerate for at least 30 minutes or until completely set and firm.