I can't find any official docs that cover this, but the problem was pretty simple after all. I am used to convention Fakes uses for simple methods, where you just assign a Func to the shimmed method delegate you're interested in, like so:
shimAccount.CreateCloudTableClient = () => { return shimTableClient; };
When generics are involved, though, Fakes creates a method that takes a Func as an argument instead of directly exposing the delegate. So what I needed was:
shimTable.ExecuteQueryOf1TableQueryOfM0TableRequestOptionsOperationContext<MyEntity>((query, options, context) =>
{
return new List<MyEntity>();
});