It doesn't look like there is a built-in way to do this. If you need this for a one-off, you could use the browser developer tools to break at the right moment and change the
itemsPerPage value. For me using redash 2.0.0, this was in client/app/components/dynamic-table/index.js with a line that says:
this.itemsPerPage = this.count = 15;
If you break one line after this and then evaluate the following in the console, the results will show as you expected:
this.itemsPerPage = this.count = 30;
It would be nice to have a query parameter or something to do this regularly though.