Pads can touch slightly when the brakes aren't in use, this is normal - they only retract a tiny amount when the lever's released. If you had too much space between pads & disc, your lever travel would be too much.
If your brakes are binding you'll know, as your bike won't roll well in neutral, say when coasting up to a traffic light. Binding is usually caused by corrosion behind the hydraulic seals.
To service: Remove caliper & pads then take the pistons out (Using a proper tool that grips from the inside, or use compressed air) then gently remove the seals. Use a copper wheel on a dremmel to clean the channels where the seals sit. Inspect seals and replace if damaged. Pistons should be free of corrosion. To re-assemble coat seals with hydraulic silicone grease, or (clean) brake fluid before re-fitting. Copper grease the bolts to avoid them getting seized in place.
Bleeding can be tricky for bike brakes. A Vacuum bleeding kit is usually a useful tool to own.
Avoid re-using fluid that's been bled through the system. Bungee the lever to the handlebar after finishing and leave overnight to get rid of the last few remaining bubbles in the lines. Servicing calipers can help keep them running sweetly. Too many people just push them in when fitting new pads without even cleaning the pistons... Doing this is bad practice as it can affect brake performance.
Euro RC51 SP2: HRC WSB Ti Hi-Level, T1 Airbox & Snorkel, PCIII, Dymag CA5 Carbon Wheels, Ti64 Spindles (F, R & Swing Arm), Mori Link, Maxton GP7 Shock & Ohlins 832 Forks, Brembo GP Calipers & SBK narrow track (F), Braketech Disc (R), Brembo billet Underslung x 2 Brembo RCS, Tyga Triple, 7075 Stem, Probolt Titanium all over, Babyface rearsets, MR Complete Carbon Lineup, Custom Undertail & CBR 1000 LED, Watsen LED Indicators, Harris Brace, Giles clip-ons, Corbin seat, etc. 2013 BOTY.