Over med high heat, heat oil in large kettle. Add chicken pieces, sprinkle with salt and pepper. Continue to cook over med high heat until chicken is browned. Transfer chicken to plate.
To same kettle, add onion, curry powder, ginger, garlic, jalapeno and red pepper flakes. Continue to sauté over med high heat for 3 minutes.
Stir in chicken stock, tomatoes, and cilantro. Bring to a boil, and then reduce heat to medium and simmer 10 minutes.
Ladle out about 2 cups of hot broth. Set aside.
In a different smaller saucepan, melt butter over med high heat. Add flour and whisk over med high heat until smooth and bubbly, making a roux (pronounced ROO). Gradually add the ladled broth, continually whisking. Simmer and whisk for an additional minute. Remove from heat.
Add flour/broth mixture back to soup kettle. Simmer for 3 minutes. Add coconut milk and spinach. Remove from heat. Cover for 5 minutes. Stir.
Serve in a bowl over steamed rice.