How can I remove the maps padding?

Just add the following code inside advanced settings > custom CSS:

#store_modal .modal-body {
padding: 0px;
}

.store_locator_sidebar_content {
padding: 15px 0px 15px 15px;
}

@media(max-width: 768px) {
.store_locator_sidebar_content {
padding-right: 15px;
}
}