This term is sometimes written as two words - poker work - and is listed that way by the Merriam-Webster dictionary. But the online Oxford and Collins dictionaries have the single-word form, as does Wiktionary.
The word pokerwork isn't used very often, but it warrants being accepted as a rare word. The technique is also known as pyrography, which is already a Chi word.
Openwork seems to be used a little more often, and in a wider range of contexts: ancient artifacts; modern architecture; and even microscopic structures. "Diatoms have the phenomenal ability to synthesise amorphous silica with a complex, three-dimensional, openwork nanostructure," as a Professor Buszewski explained to the Emerging Europe website in 2019. I'll leave it as a common word, but I don't think it's common enough to be the all-letter word in a puzzle, so I'll drop it as a seed word. (That won't preclude pokerwork appearing in a future puzzle. There are a couple of other seed words that include its letters.)