From Wiktionary, the free dictionary
From kuna + -se.
kuna-se
- to someplace, to somewhere
- Zajceva, N. G., Mullonen, M. I. (2007) “куда-то”, in Uz’ venä-vepsläine vajehnik / Novyj russko-vepsskij slovarʹ [New Russian–Veps Dictionary][1], Petrozavodsk: Periodika