1. Define the partner minimal tree and form view:

    <record id="view_all_customers_tree" model="ir.ui.view">
        <field name="name">All customers</field>
        <field name="model">res.partner</field>
        <field name="arch" type="xml">
            <tree>
                <field name="name" />
            </tree>
        </field>
    </record>

   <record id="view_all_customers_form" model="ir.ui.view">
        <field name="name">All customers</field>
        <field name="model">res.partner</field>
        <field name="arch" type="xml">
            <form>
                <group>
                    <field name="name" />
                </group>
            </form>
        </field>
    </record>

2. Update the action from the Adding a menu item and window action recipe to use a new form view:

    <record id="action_all_customers_tree" model="ir.actions.act_window.view">
        <field name="act_window_id" ref="action_all_customers" />
        <field name="view_id" ref="view_all_customers_tree" />
        <field name="view_mode">tree</field>
        <field name="sequence" eval="2"/>
    </record>

    <record id="action_all_customers_form" model="ir.actions.act_window.view">
        <field name="act_window_id" ref="action_all_customers" />
        <field name="view_id" ref="view_all_customers_form" />
        <field name="view_mode">form</field>
        <field name="sequence" eval="2"/>
    </record>

Now, if you open your menu and click on a partner in the list, you should see the very minimal form and tree that we just defined.