Lightly season peeled and deveined shrimp (tails left intact) with salt.
Heat canola oil in a large saucepan set over medium-high heat.
Add red bell pepper strips and cook, stirring frequently, until almost tender, 4 to 5 minutes. Add white portions of scallions, ¼ cup cilantro, garlic, and red pepper flakes. Cook, stirring, for 30 to 60 seconds. Be sure not to burn the garlic or the dish will take on a bitter flavor.
Add tomatoes and coconut milk, and bring to a simmer. Add shrimp, partially cover the pan, and continue to cook, stirring frequently, until the shrimp are just cooked, about 5 minutes. Watch the shrimp carefully. Overcooked shrimp is rubbery shrimp.
Stir in lime juice, taste, and add more salt, if necessary. Serve over rice and top with remaining cilantro and scallion greens.
Recipe printed with permission from Pam Anderson's Perfect One-Dish Dinners: All You Need for Easy Get-Togethers