Is there any way how to disable all skins RichFaces apply? They ruin my layout and override fonts, links,...
You can redefine each CSS style, but it'll be boring... Have a look at reset css, this can help you to redefine the CSS.
or, you can try to remove style:
<context-param>
<param-name>org.richfaces.CONTROL_SKINNING</param-name>
<param-value>disable</param-value>
</context-param>
<context-param>
<param-name>org.richfaces.CONTROL_SKINNING_CLASSES</param-name>
<param-value>disable</param-value>
</context-param>
or try to use the plain style
<context-param>
<param-name>org.richfaces.skin</param-name>
<param-value>plain</param-value>
</context-param>