Yelp is definitely your best friend here! Irvine is kind of an epicenter of food, so you’ll definitely have a lot of good choices. If you’re feeling Korean/Asian food, Diamond Jamboree is a must, and is very very popular here. The Crossroads has a kind of trendy atmosphere, with lots of desserts…
I live on Balboa Island and I normally go to the peninsula for bars and food. This is where I go near the Balboa pier:
Good cheap Mexican food - Great Mex Dive bars with reasonable drinks - Class of 47/The Saloon
Near the other pier: Cassidy’s bar and grill - dive bar with one of the best burgers…