Hello JR,
In order to delete the fields min and max salary, go to this file
componentscom_jajobboardviewsjajobstmpljasearchform.php
remove these lines:
<?php if (count($salary_min) > 0):
if (($salary_min[0]->field_state=='add'||$salary_min[0]->field_state=='chg')&&($salary_min[0]->display=='show_all'||$salary_min[0]->display=='hide_on_view'||$salary_min[0]->display=='hide_on_edit')) : ?>
<tr class="sectiontableentry1">
<td><label for="filter_salary_from"><?php echo JText::_('SALARY_MINIMUM'); ?></label>
</td>
<td>
<input onkeyup="NumberOnly1(this)" type="text" name="filter_salary_from" style="width: 150px;" value="" id="filter_salary_from" />
</td>
</tr>
<?php endif ; ?>
<?php endif ; ?>
<?php if (count($salary_max) > 0):
if (($salary_max[0]->field_state=='add'||$salary_max[0]->field_state=='chg')&&($salary_max[0]->display=='show_all'||$salary_max[0]->display=='hide_on_view'||$salary_max[0]->display=='hide_on_edit')) : ?>
<tr class="sectiontableentry2">
<td><label for="filter_salary_to"><?php echo JText::_('SALARY_MAXIMUM'); ?></label></td>
<td>
<input onkeyup="NumberOnly1(this)" type="text" name="filter_salary_to" style="width: 150px;" value="" id="filter_salary_to" />
</td>
</tr>
<?php endif ; ?>
<?php endif ; ?>
For other field, go to Design and Customization >> Forms customization >> Filter for Job Form, open one field and setting like this: http://easycaptures.com/fs/uploaded/825/2183915191.png