I am not sure if they updated the web application or not, however I think I have found a way to remove the transactions. In the screen where you select which transactions are taxable, unselect all the transactions and proceed to the end of the Crypto wizard. Once that was done today the transactions were all cleared out and I was able to start my import from the beginning.
Following these steps does not provide any way to remove imported transactions. There is no way to delete imported cryptocurrency entries, only to modify them. I can only remove transactions that are manually added.
This is a huge problem with TurboTax IMHO. I faced this issue, but, luckily, I didn't have many trades and I was able to manually un-check the duplicated transactions. I have a friend with ~1K trades facing this same problem, so this is a serious headache for him! Please provide functionality to "clear all previously imported transactions" from bitcoin.tax, etc.