I have a few suggestions but they depend on your exact scenario. What I can suggest is:
1) You can declare two RadToolTips for each target control and set their ShowEvent to OnClick and OnFocus. This will simulate the desired behavior.
2)You can set OnClick for ShowEvent and hook up the onfocus event of the target control and show the RadToolTip after obtaining a reference to it in the following manner:
var tooltip = $find("<%= Radtooltip1.ClientID %>");
<asp:TextBox ID="TextBox2" runat="server" onfocus="showToolTip()"></asp:TextBox>
3) You can set ShowEvent=FromCode, hook up the desired events and programmatically show the tooltip (as in 2) but with full control over events that show the tooltip)
I hope that you will find my suggestions helpful, let me know how it goes.
the Telerik team