In a saucepan on medium-high heat, stir together the curry paste with 2 tablespoons of the coconut milk (preferrably the creamy part from the top). Fry for two minutes, stirring occasionally.
Add all other ingredients to the saucepan: the remaining coconut milk, peanut butter, brown sugar, soy sauce and lime juice. Stir to combine until smooth.
On low-medium heat, simmer the sauce for about 10 - 15 minutes, stirring occasionally. The sauce will thicken up a little bit while cooking, but will get even thicker to dipping consistency as it cools down a bit.
For substitution ideas and serving suggestions, see the post above.