Is there any way to get light flares in a canon m50 and its 15-45mm lens?
The focal length of your lens does not necessarily determine wether or not you will see lens-flares. Lens-flares appear by reflecting light within the lenses, often bouncing around which in on itself would be considered a mistake. So chances are that with cheaper lenses, you will actually see more lens-flares than with an expensive zeiss-prime lens.

There are some tricks to make lens-flares more apparent: You can use a rubber-band and stretch it in front of the lens horizontally - the rubber-band will be almost invisible since it's so out of focus, however, the reflected light will be caught by it and give you an almost anamorphic-looking lens-flare. For more dyi-tips and tricks concerning lenses I recommend you check out the FilmRiot Youtube channel, or the IndyMogul one. They hinted me towards the rubber-band trick for example.