In a large bowl, stir together the peanut butter, coconut oil, maple syrup, vanilla, and salt until combined. Add the almond flour and maca, if using, and stir to combine (the mixture will be thick). Fold in the chocolate chips and press into the pan. Place in the freezer so that it firms up a bit while making the next layer.
In a small food processor, pulse the walnuts, cacao powder, and sea salt until the walnuts are well chopped. Add the dates and pulse to combine, adding 2 tablespoons water if the blade gets stuck. Process until smooth, then spread onto the cookie layer. Sprinkle with sea salt if desired. Freeze for 30 minutes (this will help them firm up, making them easier to cut). Remove and slice into bars. Store remaining bars in the fridge.
These bars freeze well. To thaw, let sit at room temperature for about 15 minutes.