I either use the George Foreman grill, or I "sautee" it with a mix of water, EVOO and some spices.
On the foreman grill, I first let it sit in a marinade in the fridge for like 30 minutes, then make sure the grill is as hot as it's gonna get and throw some chicken on it. I leave it in there for about 7 minutes, give or take, do NOT press down or you'll drain the meat and it will come out dry. I cut a few diagonal lines across each piece, just to see the color of the meat inside, and then flip it over, wth the cut side down, for about 1 or 2 more minutes. I store in an airtight plastic container. When I reheat, I sprinkle it with a bit of water before puting in the microwave the next day.
If I sautee, I heat up the water/oil/seasoning mix, add a few pieces of onion, or some garlic, depending on the seasonings I use... let that simmer for a while, then put the chicken in there... make sure the liquid comes up to about level with the meat, cover and reduce the heat, let it just cook in that for a while, flip it over after 5 or 6 minutes. Cut across the thickest part after abotu 10 minutes to see if it's cooked... it comes out nice and moist using this method...