There are multiple ways to access the HTML Reports feature in CRM for iPad. For example, some reports are accessible using the Home Page of the iPad app, while Account-related reports are accessible from the Account Detail page or the Timeline View. Depending on what types of reports users need they may not need to see the icons in various places through out the application.
How can the HTML Reports buttons be hidden in CRM for iPad?
Removing access to the Record Type for the reports that are not being used removes the corresponding buttons. For example, removing a user's access to the Account_Reports_vod Record Type on the HTML_Report_vod object removes the buttons from any Account-related page.
CRM Help Documentation: Advanced Functionality for MyInsights