You might be interested in my visual top in Tk at ztk-visual-top-w-kill or ztk-cpu-mem-logger for a single process. It will make it easy to spot cpu and mem spikes, and kill them quickly. Otherwise just watch the app with top itself. You could setup a monitoring script that will launch your app, then watch it's pid for excessive cpu or ram usage, maybe signalling you if it occurs. Another option is to set "nice" limits on the app, and if you notice it running at max nice level, then debug it.

If you are only interested in monitoring a single app, you can try linux memory leak monitor. Then just put "use MeM;" in your script, and it will put a little Tk window in the screen corner, showing the current memory usage. I use it often to test my apps for memory leaks.