"The sandwich is tasty!"
Translation:Kanapka jest smaczna!
Nope. Dropping the verb(or „to”) from copula is only a thing in East Slavic languages(and I'm not even sure if you can do that with a [noun] is [adjective] copulas too), IIRC – this might be acceptable in Ukrainian or Russian, but Polish is a West Slavic language and you can't do that, I'm afraid. ;)
I have an example of a poem/song with a sentence beginning with the construction "[noun] to [adj.]": http://www.kaczmarski.art.pl/tworczosc/wiersze/scena-to-dziwna/ (but of course poetry has its own rules and in this example "[noun] to [adj.]" isn't the whole sentence).