What do you do when your toddler doesn’t eat dinner?

My 18 month old had a full on tantrum today at dinner. Refused to eat. I tried again a half an hour later and it was the same thing. But then he oullediut his Cheerios 🤦🏻‍♀️ I didn’t give him any though...should I?

I’m worried he will wake up in the middle of the night hungry. What should I do?