is there any dams in the kings canyon national park?

Yes, there are some in the area. Hume Lake, which is inside the Sequoia National Forest, just outside of the park is created by a man-made dam.

http://www.nps.gov/seki/planyourvisit/driveviewfal...

There is another man-made dam, that is within Sequoia & Kings Canyon, in the Mineral King area that is on Crystal Lake. It was built in about 1905 and is still operated by Southern California Edison.

http://www.nps.gov/seki/planyourvisit/mkdayhikesum...

There are even more natural dams within the park. This area was once heavily glaciated, and many of the existing lakes in the park are the result of the landforms created by this glaciation. Many of the cirque lakes, also called tarns, in the high Sierras were created by dams of rock and sediment known as glacial moraines. These glacial moraines are piles of rock and sediment pushed forward by glaciers and left behind as they receded.

http://www.nps.gov/archive/seki/snrm/geology/geolo...

No, but there was a lot of debate about this in the early 20th century.

Some people wanted to build a dam at the western end of the valley, while others wanted to preserve it as a park.

The debate was settled in 1965, when Kings Canyon and Tehipite Valley was added to the already existing Grant Grove National Park (Kings Canyon National Park has 2 sections - a small section called General Grant Grove and the rest of the park located to the east of the Grove).