Starting on line 18 in your /public_html/templates/ja_xenia_ii_gamer/ folder, resides index.php.
(There is also reference to this customization in the Readme included with the template)
you would change the following:
# BEGIN: TEMPLATE CONFIGURATIONS ##########
####################################
#support extra color themes
$ja_color_themes = array('default', 'blue', 'orange'); // You can add more color array if needed
####################################
# Change the width of the template
$ja_width_default = 'wide'; // 'narrow': 800x600; 'wide': 1024x768; 'auto': fluid width
# default color
$ja_color_default = 'orange'; //blank for default, else pick one of in extra color themes $ja_color_themes
#font size default
$ja_font_size_default = 3;
# Enable users option
$ja_tool = 3; // 0: disable all; 1: disable color, enable font; 2: enable color, disable font; 3: enable all.
to the following:
# BEGIN: TEMPLATE CONFIGURATIONS ##########
####################################
#support extra color themes
$ja_color_themes = array('default', 'blue', 'orange'); // You can add more color array if needed
####################################
# Change the width of the template
$ja_width_default = 'wide'; // 'narrow': 800x600; 'wide': 1024x768; 'auto': fluid width
# default color
$ja_color_default = 'default'; //blank for default, else pick one of in extra color themes $ja_color_themes
#font size default
$ja_font_size_default = 3;
# Enable users option
$ja_tool = 1; // 0: disable all; 1: disable color, enable font; 2: enable color, disable font; 3: enable all.
To basically exclude the color options altogether and have orange as default; note you can still change font sizes..
Let me know if this helps