Verbtime uses the rules listed here to build reflexive verbs.
Simple tenses
Singular I Pers Pron + [verb] + me
Singular II Pers Pron + [verb] + je
Singular III Pers Pron + [verb] + zich
Plural I Pers Pron + [verb] + ons
Plural II Pers Pron + [verb] + je
Plural III Pers Pron + [verb] + zich
Example: Indicative Past, Singular II of "zich wassen" = "jij wast je"
Composed tenses
Singular I Pers Pron + [hebben] + me + Voltooid deelwoord / Past Participle (verb)
Singular II Pers Pron + [hebben] + je + Voltooid deelwoord / Past Participle (verb)
Singular III Pers Pron + [hebben] + zich + Voltooid deelwoord / Past Participle (verb)
Plural I Pers Pron + [hebben] + ons + Voltooid deelwoord / Past Participle (verb)
Plural II Pers Pron + [hebben] + je + Voltooid deelwoord / Past Participle (verb)
Plural III Pers Pron + [hebben] + zich + Voltooid deelwoord / Past Participle (verb)
Example: Indicative Present Perfect, Singular II of "sich wassen" = "jij hebt je gewassen"
also see:
Dutch Verb Table, Overview
Reflexive verb building, example verb