Creating a custom search to produce contributions as results
Start with the code for Find Contributions (https://github.com/civicrm/civicrm-core/blob/master/CRM/Contribute/Form/SearchContribution.php) and customize it as necessary to get the results you want, eg by hardcoding some values.

Next, choose a task similar to what you want to do from the list at https://github.com/civicrm/civicrm-core/tree/master/CRM/Contribute/Form/Task, and copy and modify it as necessary. Next, after reviewing  https://github.com/civicrm/civicrm-core/blob/master/CRM/Contribute/Task.php, find a hook like buildForm to modify the search form so it includes your new task(s).