• “Definify” has an excellent search function and many Chinese characters have the Romaja and Hangeul. For example, here is the entry for “寺” (temple, sa, 사):
http://definify.com/word/寺?q=寺

• “SayJack” needs a better search function. But it is a gold mine for both Hanja and Hangeul:
https://www.sayjack.com/korean/learn/

• I use wiktionary heavily. Almost every single Chinese character has a very helpful “Korean” sub-entry. Here’s the one for “十” (십, ship, ten)
https://en.wiktionary.org/wiki/十#Korean

• Korean Reader for Chinese Characters (KLEAR Textbooks in Korean Language, 10) Bilingual Edition
by Choon-Hak Cho, Yeon-ja Sohn, Heisoon Yang
https://uhpress.hawaii.edu/title/korean-reader-for-chinese-characters/

• Someone went to the trouble to create a Memrise course for the above book. I highly recommend it!!
https://app.memrise.com/course/1831033/korean-reader-for-chinese-characters-hanjahanjahan/

•Speaking of Memrise, I am in the process of creating a course with all the Hanja (and components) from the Heart Sutra:
https://community-courses.memrise.com/community/course/6363776/xuanzangs-heart-sutra-in-sino-korean/

• Chinese Character Cognates: 808 Common Hanzi Kanji & Hanja with online pronunciation guide for Mandarin Japanese & Korean
by Joon Geem
https://www.amazon.com/Chinese-Character-Cognates-Mandarin-Japanese/dp/099409115X