Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you: to carve up the steak, you wish you could use a knife, but you don't have one. Instead, you'll have to use your keys (きざ) to cut it. Imagine trying to cut up the steak with these keys. It's very difficult.
I can’t be bothered to cut up the green onion.