In a medium-sized bowl, combine the peanut butter, honey, vanilla, and salt. Microwave for 20-30 seconds and stir until combined.In that same bowl, add in the oats and rice krispie cereal. Stir together until completely combined. Add in the cocoa powder to your taste preference.Add in the chocolate chips if desired.Form balls with the mixture and then flatten the balls in your hand to create a cookie shape.Store cookies in an airtight container for 4-5 days (I keep mine in the fridge) or freeze for up to 3 months.