Is an Ashkenazi permitted to eat a dish that was cooked with kitniyot on purpose, but one can remove the kitniyot from his plate?
For example: a dish made with some peas by a sefardi, can one remove the peas and eat the dish?
Kitniyot are batul berov (See Orach Chayim 453:1 and commentaries), so if the volume of kitniyot is a minority there is no problem with an ashkenazi having it. Of course all the typical rules of batul berov apply (for example, it doesn't work if you can recognize the component in question, along with many other considerations), so you need to consult a competent halachik authority in any case. It is definitely worth asking though.
Also, this is only "bdieved", so ashkenazim shouldn't go cooking minority-kitniyot dishes a priori.