Yes, both are stressed on the first syllable so it's actually FI-ka and FICK-a. In fika, the i is long and the k short; in ficka, the i is short and the k sound long. For people who only speak Russian, the big problem of course is the difference between long and short syllables, but since you're also a native speaker of German, that's not a problem for you.

All two syllable words in Swedish have either akut accent (= accent I) or grav accent (aka accent II), but the difference is rarely distinctive. In some dialects, they are never distinctive. In some cases, which accent a word has also varies between different dialects.

fika is accent 1 and ficka is accent 2, but in reality you can ignore that – the most important difference between fika and ficka is the respective length of the vowel and consonant.

I'd also like to recommend the great videos by blehg, there's a list here where you can find a link to a great one about pitch accent: https://www.duolingo.com/comment/6502614

To me as a native Russian and German speaker they sound identically stressed, since "our" (both Russian and German) stress depends on "accoustic intensity" - ie loudness and distinctive pronounciation, rather than tonal features, that Swedish seems to be using in some cases. That's where my question comes from.

Tack så mycket för hjälpen!

I think this is crucial knowledge for beginning learners of Swedish. Had I known this in the beginning, I would have memorized the accent with the word from start... (Though I think I can remember most of the pitch 2 words my friend uses frequently, since they have a very distinct sound)

Yes. It would seem they have similar rhythmic values, and since letters do not necessarily have emotions, they are not literally "stressed". Thus, tonal stress seems to be what I meant :)