We have learned that "I eat oranges" goes as "orenji wo tabemasu" and "I like oranges" as "orenji ga suki desu"! But is there sentence to say "I like (suki) to eat(taberu) oranges" ? Or does オレンジが好きです already include all kinds of activities?
Like you said,「オレンジが好きです」means "I like oranges." Similar with English, and with context, one can assume that you like oranges because you like eating them. But if you really want to be specific, and say that you like eating oranges, you can say「オレンジを食べるのが好きです」. But simply「オレンジが好きです」should convey that you like to eat oranges.