This place is very charming, with a very "in" style--salvaged dining room chairs, mason jar chandeliers, rusty old doors dividing the room, a vintage hutch in the corner, and tin ceiling tiles. It is a very cute place for a date. I heard both English and Spanish in the restaurant, but it's probably more tourists overall than locals.
The menu is all pescatarian with a good number of vegan options. The waitstaff speaks English well and knows exactly what's vegan and what's not.
I went here twice, and the food was of very high quality. Once I got the signature rice dish and another time I got a portabella special over red quinoa. Both times the food was tasty and beautifully presented.
I only have two complaints: 1. For the price (~$20 for an entree), the portions are very small. Obviously this is normal for higher-price restaurants, just be aware going in that you'll likely want a cup of soup or an appetizer (or both) on top of your entree. 2. There were no vegan desserts. For a place called "green table," you'd think they'd have a bowl of fresh fruit at least.
Overall: nice place for a date in Old San Juan, but be prepared for the higher price and small portions.
Cons: High-priced, Small portions, No vegan desserts