In Android we have a way to view running tasks and RAM usage. Does Windows Phone have something similar? I think it is must for a smartphone.
The closest you have is in the Battery Saver app for monitoring power consumption (albeit only when not connected to external power) - the reason there is nothing more complex is that apps is that there is only ever one app running in the foreground - the others in the task switcher are suspended, and not consuming any valuable resources (they remain in memory, but the operating system will kick them out if memory pressure means the space is needed).
Apps can have background tasks which will show in battery saver, on the usage page as either "allowed" or "not allowed" - if neither shows, that app doesn't have any background tasks; you can also tap on an app to disable its background task, if you'd like - this may disable background tasks like updating your lock screen or weather forecasts on a live tile, for instance.
Actually there isn't, and theres also no need for one as on Windows Phone there can only be one app actively running in the foreground. The OS frees up memory from suspended apps when needed. You can also manually close those apps through the task switcher by holding the back button.
There are Background Tasks which you can manage through the Battery Saver app, but those only run periodically at times and with memory limits that wont disturb the app currently running in foreground.