Σάντουιτς is neuter, therefore goes with το. It's a loanword, so its ending is irrelevant for the grammatical gender. In fact, words ending in -ς, while mostly masculine (δρόμος=road, επαρκής=sufficient), can also be feminine (οδός=street, επαρκής) or neuter (δάσος=forest, επαρκές).
Yes, it does but there is no reason at this early stage to go into how to construct the future. This Skill is meant to teach basic phrases; in later Skills you'll get more experience in how they are constructed.