Someone posted a cute article from xkcd about one-handed sentences in Qwerty and whether anyone wanted to do the same for Colemak, but it disappeared.
Here was the qwerty one-handed sentences article
https://what-if.xkcd.com/75/
I downloaded this list of English words(http://wordlist.sourceforge.net/), which looks pretty comprehensive, and I got the following.
Colemak (422 left hand, 348 right hand, 770 total words)
right-hand words, http://pastebin.com/kxpewGGY
left-hand words, http://pastebin.com/RnBz5FLs
QWERTY (2163 left hand, 301 right hand, 2464 total words)
Dvorak (138 left hand, 8 right hand, 146 total words)
I included the resulting word lists for Colemak in case you want to construct fun sentences.
Right-Hand
Longest(10 chars): millennium
Notables: hellhole, homelike, homonymy, honeymoon, illumine, jejunely, jellylike, julienne, kneehole, linoleum, molehill, nonillion, nonunion, noumenon, unlikely
Left-Hand
Longest(11 chars): abracadabra
Notables: abstract, abstracts, attracts, baccarat, bastards, braggart, braggarts, cascaras, cassavas, cataract, cataracts, crabgrass, crawdads, dastards, rattraps, sassafras, scabbard, scabbards
Dvorak Longest
Left-Hand(6 chars): kookie, yippee, exequy, opaque, papaya, yippie, yuppie, upkeep
Right-Hand(3 chars): ssh, shh, nth, lbw, brr, hmm