At cozy Cafe Catania in Brooklyn Heights, the sandwich list is impressive. But I'd recommend you skip the menu and go for a manager's suggestion: their sarde a beccafico on semolina with a bed of arugula and a healthy squeeze of lemon ($11.75). Pricey, but more than worth it.
'sardine sandwiches' on Serious Eats
Sardines and stuzzicchino, a spicy marinated vegetable mix, are enveloped in pillowy bread made in-house. The stuzzicchino, almost an Italian take on salsa, is made with chili flakes, eggplant, and other assorted vegetables, and added serious heat to the sandwich, which was nicely counterbalanced by the mild sardines.
Local Mission Eatery is dedicated to living up to its name. Everything in the restaurant is made from locally sourced ingredients, even, it seems, the decor (a wall of lovingly used cookbooks). Yet a meal here is more than just a ho-hum pile of local roasted veggies. They serve more assertive dishes such as tongue with mushrooms and pears, or this Cured Sardine Sandwich ($9).