I had this same problem with my son, who sounds like he is a lot like your son in personality. When I would pick him up at daycare he would routinely try to hit me (sometimes succeeding in hitting me with an open-hand on my face), and would often melt down. I consulted with someone I know who has been a preschool teacher for 30+ years and she reminded me, first of all, that I should feel privileged because a lot of times preschoolers "keep it together" all day long, but wait for you to come home because they have a lot of emotions bottled up and they feel safe melting down in front of you. (That didn't make it any easier to take, but I tried to remind myself that he was melting down because he loves me!)
She recommended a few things--first, if you find that this ends up happening in certain situations (in my case, it was when I picked him up to take him out to the car that he would try to hit me--and sometimes when I would put him in his carseat that he would melt down), then do the whole routine in a different way. I worked with my daycare provider to help me take him out to the car and to get him in his carseat, and that helped. I also tried to be very consistent in how I reacted--if he tried to hit me, every single time I would grab his hand and say (as calmly as I could muster) "We don't hit. That hurts mommy." (Over and over!)
Some kids--especially "spirited" ones--have a hard time transitioning, and if you ask them to to switch gears and leave too quickly that can cause the tantrum. So I also tried to allow a little extra time after I got to daycare and didn't ask him to leave immediately, but gave him an extra 5 to 10 minutes to adjust (playing with toys, saying goodbye to friends). You may want to read "Raising your Spirited Child," which I have found pretty helpful in dealing with issues around transitioning for my spirited and challenging son.
The good news is that my son is now 5 1/2 and is long past all of that. It was at its peak right around 3 1/2, but steadily got better as he headed towards 4. When these behaviors are happening they feel like they will last forever, but they do pass!