Heat a large skillet over medium-high heat. Add 2 teaspoons of the canola oil and swirl to coat the pan.
Add the shrimp in a single layer and cook about 1 minute per side, until pink and opaque. Transfer the shrimp to a plate and set aside.
Add the remaining 1 teaspoon canola oil to the skillet.
Add the finely chopped 1/2 yellow onion and cook over medium heat for about 5 minutes, stirring occasionally, until softened.
Add the 1 teaspoon ground ginger, 1 teaspoon ground cumin, 1 teaspoon ground coriander, 1 1/2 teaspoons ground turmeric, 1 teaspoon curry powder, 1 teaspoon paprika, 1/2 teaspoon chili powder, 2 cloves minced garlic, and 1/2 teaspoon Kosher salt. Stir continuously and cook about 30 seconds, until the spices are fragrant.
Pour in the 15-ounce can of tomato sauce and stir to combine. Bring the mixture to a gentle simmer.
Stir in 3/4 cup lite canned coconut milk and return the sauce to a gentle simmer.
Return the cooked shrimp to the skillet, stirring to coat them in the sauce, and cook just until the shrimp are heated through (about 1–2 minutes).
Remove from heat and garnish with cilantro and chili peppers if desired. Serve.