warm it up a little first.
edit, to elaborate:
the fat in coconut milk (coconut oil) melts around 76 degrees. so if you let yr can sit in some hot water for a bit and then shake it - it mixes up better. i sometimes pour it in a pan and heat it up.
additionally, look for brands that have the highest calories per serving; "coconut milk" is just coconut meat + varying amounts of water. i figure the less water, the less mixing.. unless it has stabilizers/emulsifiers, as you mentioned. yuk.
if i want it really creamy i'll open it without shaking and dump the watery stuff and only use the 'lumps'.