How do I goad a foreign power into attacking?

All Crusades, Jihads and other Holy Wars are all started by the religious leaders declaring one, for Jihads this is the Sunni and Shia Caliphs. There is no direct way of starting a Crusade or 'goading' them into a Jihad - instead your best option is to try and gain control of important religious territories, this will eventually lead to a religious war being triggered.

Crusader Kings 2 works by applying religious weight to different territory, the higher the weight the more important it is for that religion and thus the more likely it is to trigger a religious war. In your case you are looking to trigger a 'Jihad' which means you need to target the most important Muslim territories, listed below in descending order of 'weight' I have listed the most important Muslim territories...

• County of Mecca (obviously)
• Duchy of Medina
• County of Medina
• Kingdom of Persia
• Kingdom of Mesopotamia
• Kingdom of Egypt
• Kingdom of Jerusalem
• Duchy of Jerusalem
• County of Byzantion
• County of Jerusalem

There are more territories than just these but they are the most significant and most likely to trigger a Jihad if under threat or are under the occupation / rule of a Christian or non-Muslim leader.

Additionally if any of the following conditions are met with regard to territory then a Jihad will automatically begin...

Caliphate Endures - Year is 1187 AND Caliph exists

Fall of Jerusalem - Jerusalem held by non-Muslim

Fall of Mecca - Mecca held by non-Muslim

Center Collapsing - Baghdad, Damascus or Cairo held by non-Muslim

Africa in Danger - Marrakesh, Tunis or Al Dzajir held by non-Muslim

Besides taking territory and directly confronting the Muslims all you can really do is wait for a Crusade / Jihad to begin by letting the religious leaders declare it on their own. You can of course 'sow dissent', 'assassinate' and generally cause as much disruption as possible to the Caliphs to make sure there as fired up as possible but this is unlikely to do much other than make people who probably hate you, hate you more...