Mix the garlic, sambal, and kecap manis in a small bowl.
Heat 1 tablespoon oil in a wok over high heat. Stir-fry the chicken until browned and cooked through, about 4 minutes. Add the prawns and cook until opaque, 2 minutes. Transfer to a plate.
Fry the Rice:
Add the remaining oil to the wok. Scramble one egg until just set, then add the spice mixture and cook for 30 seconds.
Add the cold rice and toss vigorously until every grain is coated and hot, about 3 minutes.
Return the chicken and prawns to the wok and toss with the scallions.
Fry the Eggs and Serve:
Fry the remaining eggs in a small skillet until the whites are crisp and the yolks are still runny.
Divide the nasi goreng among bowls and top with a fried egg, cucumber, and crispy shallots.
Notes
Cold, dry rice gives the best texture.
Kecap manis is sweet and thick; regular soy sauce is not a direct substitute.
Cook quickly over high heat for the best smoky flavor.