Ecstasy widespread after a number arriving at Spanish island (8)
I believe the answer is:
tenerife
'spanish island' is the definition.
(I've seen this before)
'ecstasy widespread after a number' is the wordplay.
'ecstasy' becomes 'e' (informal term for the drug).
'widespread' becomes 'rife' (I've seen this before).
'after' is a charade indicator (letters next to each other).
'a number' becomes 'ten' (ten is a kind of number).
'e'+'rife'='erife'
'erife' after 'ten' is 'TENERIFE'.
'arriving at' is the link.
(Other definitions for tenerife that I've seen before include "Strange fine tree on the Spanish island" , "Largest of the Canary Islands" , "Largest Canary island" , "holiday resort" , "There's an odd inter fee on the island" .)