Whole Sichuan peppercorns are most prominently used in Sichuan cooking where they can be the star of a dish (e.g. mapo tofu). However, the powder form is a central ingredient in the so-called "Five Spices" mix:

- star anise - fennel - cinnamon - clove - sichuan peppercorns

This "five spices" powder is used very often in Northern Chinese cooking as a meat or tofu rub.

In addition, sichuan peppercorns are often used in lushui in the south:

https://soupeduprecipes.com/chinese-master-brine-recipe/

and also it can be found in a lot of braising recipes.

True, but I'd say it's a staple of international/exported Chinese cuisine.

Honestly, I wish it was more of a staple if anything. It's surprisingly hard to find really good Sichuanese food. I've had mapo tofu that ends up tasting more like a poorly done Hunan dish because of an unpleasant sourness and thickened sauce, even in restaurants that claim to be Sichuanese.

By far though, one of the best Sichaunese dishes which is unfortunately (and surprisingly) overlooked is their whitefish. If you know you know.

There's an extremely good/authentic Sichuan restaurant in one of the more boring parts of the SF Peninsula (Millbrae) called Yummy Szechuan.

Tei Feng. The best. Milwaukee does it proper. Szechuan Restaurant on National.

Dried peppercorns are found in most Chinese kitchens. It's not used in every dish, but it's certainly a staple in any Chinese pantry. The related Sansho peppercorn is used like black pepper in Japanese cooking.

Dried peppercorns are not necessarily Sichuan peppers, which are distinctly used in Sichuan cuisine. So while it may be a staple in Chinese pantry (and mine too) it is certainly tied to specific cuisine.

Looks like we're quickly going into semantics but I maintain that it isn't "a staple" of Chinese cuisine in general. It's very regional and many regions will not notice a shortage of them.

Bread is a staple of French (and European) cuisine, cayenne pepper is found is found in most kitchens but isn't.