Sansho pepper (sometimes called Japanese pepper, or Korean pepper) is a tree in the citrus family that produces peppercorns that are used in Japanese cooking. The peppers are sometimes used whole, and sometimes crushed into a powder that is used to season various dishes. Sansho is related to the well-known Chinese sichuan pepper, and both have similar properties.

Being a part of the citrus family, sansho peppercorns have a tangy, citrus-y flavor that is quite distinct. In addition, the peppercorns create a tingling sensation inside of the mouth that can almost feel numbing if a large amount of pepper is eaten at once. The distinct flavor and tingling affect produced by the peppers turn some people off, but many others love the flavor and enjoy the unique feeling that it produces in the mouth.

Sansho pepper is most commonly seen in it's powder form, and is used as a condiment for anything from chicken to ramen. The quintessential use of the spice, however, is as a condiment on grilled eel. This combination is delicious, and definitely worth trying!
Another use is as one of the 7 ingredients in 七味唐辛子 (shichimi togarashi), the classic Japanese spice mixture found as a condiment in restaurants everywhere.

This is a super simple onigiri recipe that is quick and delicious.

Ingredients:
-Cooked Japanese rice, cooled to room temperature
-Salt
-Canned tuna
-Mayonnaise
-Powdered sansho pepper
-Nori (optional)

Directions:

1. Drain the excess water from the tuna can. Add mayo, a little at a time, until the tuna is creamy. Add sansho powder, bit by bit, until the mixture has the level of spice that you prefer.

2. Spread rice on a piece of plastic wrap, and sprinkle with a small amount of salt. Add a spoonful of the tuna mixture to the center of the rice and wrap it up so that the filling is surrounded by rice.

3. Form the onirigi into your desired shape.

That's it! You can wrap with nori before eating, or eat as it is. Enjoy!