In a large skillet, heat oil over medium-high.
Add scallion whites and red curry paste and sauté until onion is tender, about 1-2 minutes.
Add garlic, shrimp, and season with salt and cook until garlic is fragrant, 1-2 minutes.
Add coconut milk and fish sauce. Stir to mix well. Add vegetables and toss to coat. Bring mixture to a simmer and cook for 2 to 3 minutes, or until shrimp is cooked through. Shrimp should no longer look translucent, but opaque.
Serve with rice, cauliflower rice, noodles, or spaghetti squash and top with desired garnishes.