<aura:iteration items="{!v.olis}" var="oli">
    <tr class="slds-hint-parent">
        <!-- Other columns... -->
        <td role="gridcell">

            <lightning:buttonMenu iconName="utility:down" name="{! 'lquickAction_' + oli.Id}" alternativeText="Actions" onselect="{!c.buttonMenuQuickActionSelected}">
                <lightning:menuItem label="Do the Important Thing" value="4" />
            </lightning:buttonMenu>

        </td>
    </tr>
</aura:iteration>