Hello! As For your question,very few people know this so I will be "Leaking" this secrect out to you! first, go to namemc.com , click your name on the top right corner, then click "Edit Profile, Then click, "edit emojis" , Click "Request Emoji", ENJOY!
Currently the only emoji you can get beside your name is the Santa hat emoji. You can get this one by clicking the Santa hat option on your skin and wearing it. All other emojis are not yet obtainable, though they are being worked on.