This quick fish stir-fry celebrates summer’s bounty with the addition of chopped tomatoes and green beans but has enough lemongrass, ginger and chile to taste delicious any time of year. Most of the foundational flavor in this recipe gets infused into the dish with the help of an aromatic paste that leans into Southeast Asian flavors created by blitzing cilantro, ginger, garlic and lemongrass in a food processor. (The food processor does most of the heavy lifting and is important for breaking down the fibrous lemongrass.) You’ll cook the paste in oil to deepen the flavors, then add tomatoes, which melt into the mixture and create a sauce that will enrobe the fish and green beans. Serve with your choice of steamed rice or toss into cooked or fried noodles.