Make oat flour: Process oats in a food processor or spice grinder until flour-like consistency.
Add to mixing bowl along with rest of the veggie burger ingredients.
Use a potato masher and smash black beans and rice. Mix until all the ingredients are fully incorporated. The mixture should be sticky and dough-like. If the mixture is too liquidy, add more ground flaxseed or oat flour. If too firm, add a small amount of water.
Using a 1/3 cup, scoop veggie burger mixture and form into patties using hands. Transfer to a baking sheet.
Bake for 20 minutes, flip, and bake for an additional 10 minutes.
Make Chipotle Crema:
Add all ingredients to small mixing bowl and mix well. Add more adobo sauce for heat, or lime juice for more acidity.
Add veggie burger and desired toppings to a hamburger bun. Enjoy! Veggie burgers keep in the fridge for about 1 week or in the freezer for up to 6 months.