the first pict looks like a red macro growing Macro gives the tank character so I would leave it , just watch as it grows and keep it trimmed so it don't get over whelming , depending on how big a patch you want . I keep my macro's around 4 to 6 inches in diameter making them bush up , the herbivore fish love to snack on them as it's part of their natural diet .
now if you don't want it remove those rocks scrape off as much as you can , than wash off the area with peroxide and use a tooth brush for scrubbing this will help kill it off , than rinse off the rock with some tank water in a bucket than you can return those rocks to the tank . you may need to repeat this process every week or so till it all dies off .
in the second pict I'm not sure what your looking at , I see something in the tunnel hard to see but I'm thinking it could be more of that macro like on the first rock , the white patches on the front of the rock looks like some coralline dyeing off it could also the reflection off your light .