Prep the shrimp: Pat shrimp dry with paper towels. Season lightly with salt and pepper. This helps them sear and not steam.
Warm the pan: Heat oil in a large skillet over medium-high.
Add onion and bell pepper. Cook 3–4 minutes until softened and slightly golden.
Build the aromatics: Add garlic and ginger. Stir 30 seconds until fragrant.
Add red curry paste and cook 1 minute to wake up the spices.
Make the sauce: Pour in coconut milk, stirring to dissolve the curry paste. Add fish sauce and sugar. Bring to a gentle simmer.
Add tomatoes and simmer: Stir in cherry tomatoes if using.
Simmer 3–4 minutes to thicken slightly and meld flavors.
Cook the shrimp: Slide in the shrimp in an even layer. Simmer 2–3 minutes, flipping once, until pink and just opaque. Don’t overcook or they’ll turn rubbery.
Finish with lime: Stir in lime zest and juice.
Taste and adjust salt, sugar, and heat. Add chili flakes if you want more spice.
Garnish and serve: Take off the heat. Sprinkle with chopped cilantro or basil.
Serve hot over rice or with warm naan.