An idiom meaning to be in tense suspense or on the edge of one's seat (literally ‘to grasp sweat in one's hand’).
試合の最後の数分は観客全員が手に汗を握って見ていた。
In the final few minutes of the match, the whole audience watched on the edge of their seats.
面接の結果が発表される瞬間、手に汗を握った。
At the moment the interview results were announced, I was in tense suspense.
クライマックスの展開は本当に手に汗を握る展開だった。
The climax was truly a nail-biting development.