If you want an oral presentation, and if your students have a good level of English you should try, for example, preparing a pair work test or in groups perhaps.First, give to each group a topic, for example, hobbies, free time activities etc for present simple, and other topics for present continuous (randomly).
Second, make them prepare a dialogue or a short paragraph on the tense and topic given.
Third, make them perform what they did orally.
Prepare a rubric with aspects to consider (preparedness, intonation, correct use of tense, topic, group work etc etc)
It will take more time than a normal test, it �s more work for you, but if you want to do a different kind of stuff maybe it �ll be great.
You could also use this idea and modify it if you want.
Good luck!
