The middle finger has been in the emoji set since Unicode 7.0 in 2014, as U+1F595.
The closest you’ll get to “wanker” is Waving Hand, U+1F44B, which has the delightful side-effect of making its recipient thing you were actually saying hello.
(... much like replying “Good For You!” to an email, with the capital letters conveying your real meaning.)
Biting the hand that feeds IT
