The Spanish for sandwich is sánguche — just the English word, as it is pronounced in Spanish. That one is easy!
However, what is noteworthy is that the -w- becomes a -g-. At first, that seems odd. But then, we remember the -w- to -g- transformation: that in a lot of Germanic words, when they’re brought into Spanish, the -w- sound becomes a -g- sound. Think war/guerra, for a great example.
Suddenly, the weird letter change makes sense!