At Adrian Tropical (Malecón, Av. George Washington, 7 a.m.–2 a.m. daily, tel. 809/566-8373, US$11–20) the view alone is worth splurging on a meal like this. There are three Adrian Tropicals in town; make sure this is the one you go to. It is on the Malecón, built onto the cliffside over the water of the Caribbean Sea. The specialty is mofongo (the camaronfongo is the best), but other options are good as well, like the pescado Boca Chica, which is a big fried fish. Make sure to get a table on the patio, although there is indoor seating as well.
Trattoria Vesuvio Malecón (Malecón, Av. George Washington 521, tel. 809/221-1954, for pizza delivery tel. 809/221-3000, noon–11:30 p.m. daily, US$12–17) is a fixture in Santo Domingo [1], widely regarded as one of the top Italian restaurants since 1954. There are two Vesuvios, and they are right next to one another. The trattoria is the more casual (sleek and modern interior) of the two (Vesuvios on the Malecón is right next door). The specialty is gourmet pizza, but their art does not stop there: seafood, calzones, beef, veal, pasta, hamburgers, quesadillas—the list goes on. Vesuvios on the Malecón is well known for its seafood and is much more formal.
Links:
[1] http://www.moon.com/destinations/dominican-republic/santo-domingo