To make bottom layer: Soak agar-agar strips in water for 30 minutes; drain well. Bring agar-agar to a boil in one litre of water and cook till completely dissolved. Add sugar and stir in mashed red beans. When sugar has dissolved, pour mixture into a wet tray.
To make top layer: Soak agar-agar strips in water for 30 minutes; drain well. Combine all the ingredients together except the thick coconut milk and bring to a boil until agar-agar and sugar have dissolved.
Lastly, add the coconut milk and bring to just a boil. Turn off the heat and pour mixture over the half-set bottom layer. Chill tray before cutting jelly into neat slices.