Ditto Snack - slightly pricey but the food is always v tasty and fresh. You could also check out the early bird at La Sirene, though the food tends towards the heavier side. There's also tapas at Boqueria.
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Boqueria
53 W 19th St, New York, NY 10011
La Sirene
558 Broome Street, New York, NY 10013