I guess you are referring to L2 metaphoric receptive and productive proficiency. One methodologically sound way of investigating this with intermediate level students is to use an L2 metaphor with L1 multiple choice (reception) and L1 metaphor with L2 multiple choice (production). With advanced students, a bilingual translation task may be used from L1 to L2 and L2 to L1 to investigate metaphoric proficiency.
For more information on why to use precisely this technique see Charteris-Black, J. (2002). Second language figurative proficiency: A comparative study of Malay and English. Applied Linguistics, 23(1), 104-133.
Roughly, a multiple choice test would be feasible to test understanding (or receptive proficiency) and a completion test to test what you call creation (i.e. productive proficiency).