Cucumber-Selenium will do for you Front-end testing so you need to choose a tool for Back-end testing as well. Were you able to find a desirable tool here for Back-end testing? Most probably you need one that supports BDD framework which can incorporate cucumber to have the same workflow in both the back-end and front-end testing.
@valuoch do you find this documentation helpful? How-to: Integrate Community QA Processes and Tools into the Development Process - Documentation - OpenMRS Wiki