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Firstly, what type of scope do you have? The collimation requirements for a 114mm or 130mm newt are (based on my experience) alot less than for a 12" or 16" one. If your focuser tube came with a dust cap it may have a hole in it which is used for collimation, simply drill one yourself (making sure it is central) make sure it is big enough taht you can see the primnary in it, proably 1/8" should be OK. If you are worried about dust, put a bit of sellotape over the hole when the scope is not in use.
If you don't want to do that, you can buy a collimation dust cap (Bintel sell them for $2-50 I think). Unless you scope is bigger than 6" thats probably all you are going to need to get started.
The tape on the mirror you refer to is probably a centre spot. That part of the mirror is directly under the secondary so is not used anyway. On my small newt I simply put a black mark with a CD marker pen to mark the centre.
Really all you are looking for is to get the mirrors concentic, the cap is simply used to centre your eye so it all lines up.
As for cleaning, until you know what you are doing here is only one thing to say...DON'T. a little bit of dust has minimal effect on the image and the risk of wrecking a perfectly good mirror is too great.
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