Eat the peel, which is sweet. Then, if you like sugar (everyone else shut your eyes here)
dip the sour insides in sugar and eat them. I have my own tree which has just a few kumquats, but they are sweet all the way through - I love them. If you can find round kumquats (not the long ones), they are likely to be sweet.
The little ones that you have are absolutely wonderful as preserves, candies or as marmalade. Serve them over vanilla ice cream.