Originally Posted by Tim_Iowa

For wheel size, look at the side wall of the tire.
It will say "26 x something (559-something)" if it fits 26" diameter rims (aka 559 mm).
It will say "27.5 x something (584-something)" if it fits 27.5" rims (aka 650b, 584 mm).

It looks like the Kona Blast went to 27.5" wheels for 2014 and newer, so if yours is a 2012 then it will have 26" wheels.

There are tons of good options for "touring" style tires in 26". For the fastest ride, get a tire that has a relatively smooth tread but has a lightweight casing. Higher thread-per-inch (TPI) counts (like 120 tpi) mean a lighter, more supple casing.
Or, get something with a light tread, like the Surly Knard or Extraterrestrial, or the Scwhalbe Thunder Burt. I have 26 x 2.1" Thunder Burts (Liteskin version) on my old MTB-to-touring bike, and they're excellent tires. Still very fast on pavement, but enough tread for dry off-road surfaces.

I like how the 26 x 2.1" tires roll, but you can go with a skinnier tire (probably down to 26 x 1.5") if you're never gonna leave the road.