There are happy hours that function as post-work gatherings, fueled by discounted pitchers of beer, buckets of chicken wings, sliders and the sort of commiserating that can only happen between colleagues. If the beer is cold and the chicken wings properly sluiced in hot sauce and ranch dressing, this happy hour can be the happiest of hours. But it wasn’t until I was seated at the bar of Josiah Citrin’s Citrin in Santa Monica that I understood a happy hour’s full potential. Here, happy hour is known as Glass Off, a 90-minute stretch of food and drink specials at the bar. Instead of a truncated list of fried foods intended to coat your stomach while you sip on discounted wine, you’ll find tasting-size portions of some of Citrin and fellow chef-partner Ken Takayama’s signature dishes. Those spot prawns with young turnip and green tomato finished with a nori sabayon that normally cost $52 an order? You can enjoy a smaller portion at the bar for $22. The $49 risotto studded with Dungeness crab, artichoke and …