If you want to paste where your cursor is, you could try pasting in insert mode with:
The command above (- ctrl-r + " - ) will not add a new line.
If you have more than one line of text to paste, and want to get rid any empty space that might come along, you could create a macro:
This macro ('@q') will open a new buffer called testtext (':e testtext'), go to the first non-empty character on the line ('^') and delete until the beginning of the line ('d0'), close the buffer without saving (':bd!'), and paste the text on the original file without the initial blank spaces.
Just out of curiosity, could you give an example of a real situation? All situation I could think of, could be solved with a macro and/or a mapping. But I'm not sure what you are looking for.
Additional information about the topic:
Many tips on how to remove unwanted whitespaces
A script that deletes white spaces at the end of lines.