Well, most track frames don't have tensioners in the first place, so there's nothing to remove. They really are not necessary to adjust chain tension, and you just need to learn how to do it. As to the the chain getting slack, it does happen over time as the chain wears, but if it happens frequently, then you just need to tighten the right side axle nut more to keep the axle from slipping forward in the dropout. It takes very little axle movement to significantly increase chain slack. Most people run their chains too tight anyway.