Hearest thou (akoueis). In a rage at the desecration of the temple by the shouts of the boys they try to shame Jesus, as responsible for it.
Thou hast perfected (katērtisō). The quotation is from Psalms 8:3 (lxx text). See note on Mat 4:21 where the same verb is used for mending nets. Here it is the timeless aorist middle indicative with the perfective use of katȧ. It was a stinging rebuke.