Heat the olive oil in a large high-sided skillet over medium heat. Add the onion and cook until tender and fragrant, about 4-5 minutes.
Add the chicken and cook, stirring often, until the breast develops a bit of color, around 4-5 minutes. Season with salt and black pepper, to taste.
Add the garlic, ginger, coriander, and red curry paste. Cook for 1-2 minutes or until the spices become fragrant.
Add bell peppers and season with additional salt and black pepper, if desired. Stir to combine and cook until peppers soften and develop a bit of color, approximately 3-4 minutes.
Add coconut milk and simmer until slightly thickened, approximately 4-5 minutes. Stir in spinach, lime juice, and maple syrup. Taste and adjust seasonings, as desired. Serve immediately topped with fresh cilantro and lime slices, if desired. Enjoy!