Toast cumin seeds in a skillet until fragrant. Transfer to mortar and pestle and grind into powder (skip this step if you are using ground cumin and coriander).
Toast and grind coriander seeds in the same way as cumin seeds (see above).
Add all ingredients except for avocado oil and oat flour to a food processor or blender and pulse to combine, scraping down the sides as needed until thoroughly combined. You are looking for a crumbly dough not a paste.
Add oat flour 1 tbsp at a time and pulse again, until no longer wet and you can mold the dough into a ball without it sticking to your hands (I used 3 tbsp).
Taste and adjust seasoning as needed. Add salt and pepper if needed or any of the other spices. Don't be shy, a lot of flavor is good!
Cover blender bowl or transfer to a mixing bowl and cover. Refrigerate for 1 hour to firm up (or 30-45 minutes in the freezer if you are in a hurry) or skip this step (which I have done before). Just keep in mind that the falafel will be a bit more fragile when cooking.
Scoop out tablespoon amounts and gently form into 12 small discs.*
Heat up a skillet over medium heat and add enough oil to generously coat the pan (about 2 tbsp). Swirl to coat. Once the oil is hot, add only as many falafel as will fit comfortably in the pan at a time.
Cook for a total of 4-5 minutes, flipping them over when the underside is golden brown. Repeat until all falafel are browned (deeper brown = crispier). They will firm up a bit more when transfer to a serving plate.