Cut the chicken breast on a cutting board into equal, bite-sized pieces. Set out the red curry paste, measured coconut milk, and cauliflower rice within reach, so you can work quickly once the pans are on the heat.
Heat a small amount of oil in a braising pan or skillet over medium-high heat. Add the chicken pieces and sear them on all sides for a few minutes. Add the red curry paste and cook briefly to activate the aromas. Pour the coconut milk into the pan, stir everything well, and let simmer gently until the chicken is cooked through and the sauce has thickened slightly.
Meanwhile, place a wok or second skillet over high heat with just a touch of oil. Add the cauliflower rice to the hot pan and stir-fry for about three minutes until just tender. The grains should be heated through but must not lose their texture.
Divide the lightly stir-fried cauliflower rice among the plates. Spoon the warm chicken curry directly over it or serve alongside. Serve immediately.