For chilli tamarind sauce, stir palm sugar and 160ml water in a saucepan over low heat to dissolve sugar, then increase heat to medium-high and cook without stirring until caramelised (4-5 minutes). Remove from heat, stir in fish sauce and vinegar (be careful, hot caramel will spit), then add chilli and tamarind, and set aside to cool. Refrigerate in a sterile jar until required.
Heat oil in a large frying pan, brown ham on both sides (2-3 minutes each side), then transfer to warm plates. Crack eggs into pan and cook over high heat, basting with hot oil, until eggs are beginning to crisp on the base and yolks have a white coating, but are still runny (2-3 minutes). Top ham steaks with eggs, drizzle with chilli tamarind sauce, scatter with coriander and serve.