How do you say "hands-on experience" with this technology to an interviewer?
Solution 1:
Just say "hands-on experience". It's common parlance in the work world. Everyone will know what it means: "I've worked with this technology". Then you give some (two or three) examples of your hands-on experience.
I don't know what you mean by "my experience in this field is very limited but quite efficient and knowledgeable". First, experience cannot be reasonably described as "efficient and knowledgeable". You can describe yourself as an "efficient and knowledgeable" worker. But saying that your experience is limited seems to contradict your statement that you are "knowledgeable".
The best thing to do is prepare a statement that makes all your points in as few words as necessary to get them across to the interviewer. Don't force the interviewer to guess at what you mean. Say it clearly and directly without being too boastful or modest.
Solution 2:
'Hands-on experience' does not mean 'experience in this field is very limited but quite efficient and knowledgeable.'
Hands-on experience means,
knowledge or skill that someone gets from doing something rather than just reading about it or seeing it being done:
They will participate in workshops and get hands-on experience leading classes.
He always said he learned more about newspapers from hands-on experience than he did in the classroom.
'Efficient and knowledgeable' would be the recommended and preferred expression instead, as that is what you intend to say. I strongly feel that you mean proficient, not efficient, though.
Solution 3:
The other term you might be looking for is "practical experience", which as an interviewer I would take to mean that you have (an unspecified amount of) experience in actually using a technology, as opposed to theoretical or "book knowledge" only. Of course you could also qualify that as much or as little as you like, e.g. "some practical experience", "three months' practical experience", etc.