Download a GRF editing tool. GRF Builder or GRF Editor by Tokeiburu are common choices.

For your no-delay edits to work, your custom GRF must be the highest priority. You must edit the file to look like this example:

Open the No Delay GRF as well. Extract the modified files.

These GRFs contain modified .act (action) files that strip away the animation frames associated with skills.