By default the editors for the Grid component are located in the ~/Views/Shared/EditorTemplates
folder. There are partial views there and the name of each Partial View corresponds to the data type it is related to.
Thus, if you would like to specify a class name for the editor that is related to fields where the DataType attribute
is set to Currency you should modify the Currency.cshtml View like illustrated below.
@(Html.Kendo().CurrencyTextBoxFor(m => m)
If you would like more information on customizing the editors used in the Grid component you would find the following article interesting.