Heat the vegetable oil in a large skillet over high heat; add garlic, stir and cook until light brown, 1-2 minutes.
Add the onion, stir in, and cook until translucent, 1-2 minutes.
Add ginger and crushed tomatoes, and stir in curry powder and salt.
Add chicken and cook, stirring constantly, until the liquid has cooked off and the sauce has thickened -- be careful not to burn it!
Pour cold water into the mixture, bring to a boil and cook, uncovered, for 10 minutes.
Stir in garam masala at the last minute, just before turning off the heat (optional).
Serve over rice or grains, and enjoy!