Line a flat surface or large cutting board with a sheet of wax paper. Using a knife, make a slit in the dates without cutting them all the way through. Carefully split dates open and arrange the dates into a 3x3 grid on the wax paper, making sure they overlap a little so they stick together.

Using a heavy rolling pin, wine bottle, or the side of a sturdy cup, press and roll the dates until they form a large, smooth sheet about 1/8 inch thick. Take your time with this step to ensure the dates are evenly flattened.

Once the date sheet is thin enough, temporarily peel back the top layer of wax paper and evenly sprinkle all toppings of your choice over one side. Place the wax paper back on top and gently press or roll over it to help the toppings adhere.

Flip the date sheet over and carefully remove the wax paper from the other side. Spread a thin, even layer of peanut butter across this surface. Use a sharp knife to cut the sheet in half vertically, creating two smaller square-sized sheets.

Peel the banana and place it along the edge of one of the date sheets. Gently straighten the banana if needed, then carefully roll it up, using the date sheet to fully wrap the banana. Use a knife to cut off any excess dates if needed.

Use your fingers to press the dates together at the edges to seal the roll. Then, repeat this process with the second date sheet and banana.

Place the rolls in the freezer for 30 minutes to firm up, which will make slicing easier. Once chilled, warm a sharp knife under hot water, dry it off, and slice each roll into 8 even 1-inch pieces.

Pour the melted dark chocolate into a small bowl to serve as "soy sauce." Arrange the banana sushi pieces on a plate around the bowl and enjoy dipping each piece into the chocolate with chopsticks or your hands.