Add almonds and oats into a high-speed blender and blend on high until a flour forms. Dump into a large bowl and break up any clumps with your fingers. Add the nut butter, coconut oil, maple syrup (or agave), cinnamon, vanilla, and salt into the bowl. Stir until thoroughly combined. The dough should be fairly sticky like cookie dough. Line a mini (or regular) muffin tin with paper liners or use a silicone muffin holder. Portion the dough into each muffin cup and press down until even and smooth. To make the chocolate sauce: Whisk together the coconut oil, sweetener, cocoa powder, and salt until no clumps remain. Spoon the sauce over top each of the cups, distributing evenly. Garnish cups with sliced almonds if desired. Place in the freezer in a flat area for 30-45 minutes, until firm. Pop out the cups & enjoy immediately! These are best consumed straight from the freezer.