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!